Vulnerability-Lookup

CVE-2026-74612 (GCVE-0-2026-74612)

Vulnerability from cvelistv5 – Published: 2026-08-22 15:31 – Updated: 2026-08-25 05:40

Title

veth: fix skb length accounting after XDP frag adjustment

Summary

In the Linux kernel, the following vulnerability has been resolved: veth: fix skb length accounting after XDP frag adjustment veth exposes non-linear skb fragments through an xdp_buff. If an XDP program adjusts the fragment area, veth_xdp_rcv_skb() copies xdp_frags_size back to skb->data_len but leaves skb->len containing the old fragment contribution. After a fragment shrink, this makes skb_headlen() larger than the actual linear area. In the reproduced UDP receive path, __skb_datagram_iter() copied 1024 bytes past the actual linear tail to userspace, starting at struct skb_shared_info. The copied bytes included the affected skb's nr_frags, xdp_frags_size, and a kernel pointer from skb_shinfo(skb)->frags[0]. Real packet data was displaced by the same amount and truncated at the end. Subtract the old data_len before replacing it and add the new data_len afterwards, keeping skb->len and skb->data_len synchronized. Additionally, bpf_xdp_pull_data() can advance data_end while leaving frags present. The skb is then still non-linear, so the old __skb_put(skb, off) triggers SKB_LINEAR_ASSERT(). Use skb_set_tail_pointer() and update skb->len explicitly instead, following bpf_prog_run_generic_xdp(). Unlike __skb_put(), skb_set_tail_pointer() does not require a linear skb. A 60000-byte UDP datagram on a veth pair with MTU 64000 was shortened by 1024 bytes from its fragment area. Before the fix, all 10 runs produced corrupted payloads. After the fix, all 10 runs matched the expected payload exactly. A forced-tailroom reproducer also exercises bpf_xdp_pull_data() with frags still present; the old code triggers SKB_LINEAR_ASSERT(), while this fix passes 10/10 runs.

Severity

10 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Assigner

Linux mitre root

References

6 references

URL	Tags
https://git.kernel.org/stable/c/0c3024afabb8064b1…
https://git.kernel.org/stable/c/2f2a7f3f8b9f1bffc…
https://git.kernel.org/stable/c/41b96667d42b74bb4…
https://git.kernel.org/stable/c/cdf745b7a777f87f5…
https://git.kernel.org/stable/c/3205b0652a37255db…
https://git.kernel.org/stable/c/cb6379feaaff11c4e…

Impacted products

2 products

Vendor	Product	Version	CPE status
Linux	Linux	Affected: 718a18a0c8a67f97781e40bdef7cdd055c430996 , < 0c3024afabb8064b141f3cedcb1ddd6ab05ad9d5 (git) Affected: 718a18a0c8a67f97781e40bdef7cdd055c430996 , < 2f2a7f3f8b9f1bffc9b0488aa02b6951b2aec139 (git) Affected: 718a18a0c8a67f97781e40bdef7cdd055c430996 , < 41b96667d42b74bb4b137f1bb78b611a953c5943 (git) Affected: 718a18a0c8a67f97781e40bdef7cdd055c430996 , < cdf745b7a777f87f51666e5d8f4c6fc279bcf54d (git) Affected: 718a18a0c8a67f97781e40bdef7cdd055c430996 , < 3205b0652a37255dbb7ca8f3d942c8d8aa677c21 (git) Affected: 718a18a0c8a67f97781e40bdef7cdd055c430996 , < cb6379feaaff11c4e1e79c26c745ffa23182768a (git)	guessed
Linux	Linux	Affected: 5.18 Unaffected: 0 , < 5.18 (semver) Unaffected: 6.1.184 , ≤ 6.1.* (semver) Unaffected: 6.6.152 , ≤ 6.6.* (semver) Unaffected: 6.12.104 , ≤ 6.12.* (semver) Unaffected: 6.18.45 , ≤ 6.18.* (semver) Unaffected: 7.1.9 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)	guessed

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{
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      "affected": [
        {
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          "programFiles": [
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              "status": "unaffected",
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              "versionType": "semver"
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              "versionType": "semver"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nveth: fix skb length accounting after XDP frag adjustment\n\nveth exposes non-linear skb fragments through an xdp_buff. If an XDP\nprogram adjusts the fragment area, veth_xdp_rcv_skb() copies\nxdp_frags_size back to skb-\u003edata_len but leaves skb-\u003elen containing the\nold fragment contribution.\n\nAfter a fragment shrink, this makes skb_headlen() larger than the actual\nlinear area. In the reproduced UDP receive path, __skb_datagram_iter()\ncopied 1024 bytes past the actual linear tail to userspace, starting at\nstruct skb_shared_info. The copied bytes included the affected skb\u0027s\nnr_frags, xdp_frags_size, and a kernel pointer from\nskb_shinfo(skb)-\u003efrags[0]. Real packet data was displaced by the same\namount and truncated at the end.\n\nSubtract the old data_len before replacing it and add the new data_len\nafterwards, keeping skb-\u003elen and skb-\u003edata_len synchronized.\n\nAdditionally, bpf_xdp_pull_data() can advance data_end while leaving\nfrags present. The skb is then still non-linear, so the old\n__skb_put(skb, off) triggers SKB_LINEAR_ASSERT().\n\nUse skb_set_tail_pointer() and update skb-\u003elen explicitly instead,\nfollowing bpf_prog_run_generic_xdp(). Unlike __skb_put(),\nskb_set_tail_pointer() does not require a linear skb.\n\nA 60000-byte UDP datagram on a veth pair with MTU 64000 was shortened by\n1024 bytes from its fragment area. Before the fix, all 10 runs produced\ncorrupted payloads. After the fix, all 10 runs matched the expected\npayload exactly. A forced-tailroom reproducer also exercises\nbpf_xdp_pull_data() with frags still present; the old code triggers\nSKB_LINEAR_ASSERT(), while this fix passes 10/10 runs."
        }
      ],
      "metrics": [
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            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
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              "lang": "en",
              "value": "AV:N - Remote packets routed through container/host veth pairs reach veth_xdp_rcv_skb() after veth_xmit on the peer; cloud and edge nodes routinely forward Internet traffic across veth links with XDP attached, matching the reproduced UDP receive path.\nAC:L - The fix commit shows 10/10 reliable reproduction with a 60000-byte UDP datagram and XDP bpf_xdp_adjust_tail()/bpf_xdp_pull_data() fragment shrink; the attacker controls packet size, timing, and both veth ends without races or uncontrollable kernel state.\nPR:N - Exploitation only requires an XDP program using bpf_xdp_adjust_tail or bpf_xdp_pull_data to already be attached on a reachable veth peer; the remote packet sender needs no local account, capabilities, or authentication to trigger the bad skb length accounting.\nUI:N - No victim interaction is needed beyond normal always-on packet reception and socket delivery; corrupted payloads and leaked kernel metadata are produced automatically when a userspace process reads the affected datagram.\nS:C - veth links intentionally cross container/host network namespaces on multi-tenant servers, and skb_shared_info metadata plus kernel pointers leaked into a tenant userspace recv buffer exceed that tenant\u0027s authorized security boundary.\nC:H - Desynchronized skb-\u003elen makes skb_headlen() exceed the real linear tail, so __skb_datagram_iter() copies up to 1024 bytes past the skb into userspace, exposing nr_frags, xdp_frags_size, and a kernel pointer from skb_shinfo(skb)-\u003efrags[0].\nI:H - The same length mismatch inflates the linear region, displacing and truncating real datagram bytes in the delivered UDP buffer and corrupting application-visible data beyond intended packet bounds while compounding misuse of leaked kernel metadata.\nA:H - bpf_xdp_pull_data() can leave frags present while the old __skb_put() path hits SKB_LINEAR_ASSERT()/BUG_ON on nonlinear skbs; the commit reports deterministic kernel asserts and crashes in addition to datagram corruption."
            }
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    "datePublished": "2026-08-22T15:31:58.295Z",
    "dateReserved": "2026-08-15T05:44:03.920Z",
    "dateUpdated": "2026-08-25T05:40:38.488Z",
    "state": "PUBLISHED"
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      "cve": "CVE-2026-74612",
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      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "veth: fix skb length accounting after XDP frag adjustment",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-74612.json",
      "version": "2"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-74612\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-08-22T16:16:33.770\",\"lastModified\":\"2026-08-25T06:18:38.680\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nveth: fix skb length accounting after XDP frag adjustment\\n\\nveth exposes non-linear skb fragments through an xdp_buff. If an XDP\\nprogram adjusts the fragment area, veth_xdp_rcv_skb() copies\\nxdp_frags_size back to skb-\u003edata_len but leaves skb-\u003elen containing the\\nold fragment contribution.\\n\\nAfter a fragment shrink, this makes skb_headlen() larger than the actual\\nlinear area. In the reproduced UDP receive path, __skb_datagram_iter()\\ncopied 1024 bytes past the actual linear tail to userspace, starting at\\nstruct skb_shared_info. The copied bytes included the affected skb\u0027s\\nnr_frags, xdp_frags_size, and a kernel pointer from\\nskb_shinfo(skb)-\u003efrags[0]. Real packet data was displaced by the same\\namount and truncated at the end.\\n\\nSubtract the old data_len before replacing it and add the new data_len\\nafterwards, keeping skb-\u003elen and skb-\u003edata_len synchronized.\\n\\nAdditionally, bpf_xdp_pull_data() can advance data_end while leaving\\nfrags present. The skb is then still non-linear, so the old\\n__skb_put(skb, off) triggers SKB_LINEAR_ASSERT().\\n\\nUse skb_set_tail_pointer() and update skb-\u003elen explicitly instead,\\nfollowing bpf_prog_run_generic_xdp(). Unlike __skb_put(),\\nskb_set_tail_pointer() does not require a linear skb.\\n\\nA 60000-byte UDP datagram on a veth pair with MTU 64000 was shortened by\\n1024 bytes from its fragment area. Before the fix, all 10 runs produced\\ncorrupted payloads. After the fix, all 10 runs matched the expected\\npayload exactly. A forced-tailroom reproducer also exercises\\nbpf_xdp_pull_data() with frags still present; the old code triggers\\nSKB_LINEAR_ASSERT(), while this fix passes 10/10 runs.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"drivers/net/veth.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"718a18a0c8a67f97781e40bdef7cdd055c430996\",\"lessThan\":\"0c3024afabb8064b141f3cedcb1ddd6ab05ad9d5\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"718a18a0c8a67f97781e40bdef7cdd055c430996\",\"lessThan\":\"2f2a7f3f8b9f1bffc9b0488aa02b6951b2aec139\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"718a18a0c8a67f97781e40bdef7cdd055c430996\",\"lessThan\":\"41b96667d42b74bb4b137f1bb78b611a953c5943\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"718a18a0c8a67f97781e40bdef7cdd055c430996\",\"lessThan\":\"cdf745b7a777f87f51666e5d8f4c6fc279bcf54d\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"718a18a0c8a67f97781e40bdef7cdd055c430996\",\"lessThan\":\"3205b0652a37255dbb7ca8f3d942c8d8aa677c21\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"718a18a0c8a67f97781e40bdef7cdd055c430996\",\"lessThan\":\"cb6379feaaff11c4e1e79c26c745ffa23182768a\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"drivers/net/veth.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"5.18\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"5.18\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.1.184\",\"lessThanOrEqual\":\"6.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.152\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.104\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.45\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.9\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H\",\"baseScore\":10.0,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"CHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":6.0}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/0c3024afabb8064b141f3cedcb1ddd6ab05ad9d5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/2f2a7f3f8b9f1bffc9b0488aa02b6951b2aec139\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/3205b0652a37255dbb7ca8f3d942c8d8aa677c21\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/41b96667d42b74bb4b137f1bb78b611a953c5943\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/cb6379feaaff11c4e1e79c26c745ffa23182768a\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/cdf745b7a777f87f51666e5d8f4c6fc279bcf54d\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-25T08:50:57+00:00",
      "cve": "CVE-2026-74612",
      "id": "CVE-2026-74612",
      "initial_release_date": "2026-08-22T00:00:00+00:00",
      "product_status:known_affected": "198",
      "product_status:known_not_affected": "76",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: veth: fix skb length accounting after XDP frag adjustment",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74612.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "not set",
      "current_release_date": "2026-08-23T00:05:59Z",
      "cve": "CVE-2026-74612",
      "id": "CVE-2026-74612",
      "initial_release_date": "2026-08-23T00:05:59Z",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-74612",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-74612.json",
      "version": "2"
    }
  }
}

FKIE_CVE-2026-74612

Vulnerability from fkie_nvd - Published: 2026-08-22 16:16 - Updated: 2026-08-25 06:18

Severity

10.0 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Summary

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/0c3024afabb8064b141f3cedcb1ddd6ab05ad9d5
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/2f2a7f3f8b9f1bffc9b0488aa02b6951b2aec139
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/3205b0652a37255dbb7ca8f3d942c8d8aa677c21
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/41b96667d42b74bb4b137f1bb78b611a953c5943
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/cb6379feaaff11c4e1e79c26c745ffa23182768a
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/cdf745b7a777f87f51666e5d8f4c6fc279bcf54d

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/veth.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "0c3024afabb8064b141f3cedcb1ddd6ab05ad9d5",
              "status": "affected",
              "version": "718a18a0c8a67f97781e40bdef7cdd055c430996",
              "versionType": "git"
            },
            {
              "lessThan": "2f2a7f3f8b9f1bffc9b0488aa02b6951b2aec139",
              "status": "affected",
              "version": "718a18a0c8a67f97781e40bdef7cdd055c430996",
              "versionType": "git"
            },
            {
              "lessThan": "41b96667d42b74bb4b137f1bb78b611a953c5943",
              "status": "affected",
              "version": "718a18a0c8a67f97781e40bdef7cdd055c430996",
              "versionType": "git"
            },
            {
              "lessThan": "cdf745b7a777f87f51666e5d8f4c6fc279bcf54d",
              "status": "affected",
              "version": "718a18a0c8a67f97781e40bdef7cdd055c430996",
              "versionType": "git"
            },
            {
              "lessThan": "3205b0652a37255dbb7ca8f3d942c8d8aa677c21",
              "status": "affected",
              "version": "718a18a0c8a67f97781e40bdef7cdd055c430996",
              "versionType": "git"
            },
            {
              "lessThan": "cb6379feaaff11c4e1e79c26c745ffa23182768a",
              "status": "affected",
              "version": "718a18a0c8a67f97781e40bdef7cdd055c430996",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/veth.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.18"
            },
            {
              "lessThan": "5.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.184",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.152",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.104",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.45",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nveth: fix skb length accounting after XDP frag adjustment\n\nveth exposes non-linear skb fragments through an xdp_buff. If an XDP\nprogram adjusts the fragment area, veth_xdp_rcv_skb() copies\nxdp_frags_size back to skb-\u003edata_len but leaves skb-\u003elen containing the\nold fragment contribution.\n\nAfter a fragment shrink, this makes skb_headlen() larger than the actual\nlinear area. In the reproduced UDP receive path, __skb_datagram_iter()\ncopied 1024 bytes past the actual linear tail to userspace, starting at\nstruct skb_shared_info. The copied bytes included the affected skb\u0027s\nnr_frags, xdp_frags_size, and a kernel pointer from\nskb_shinfo(skb)-\u003efrags[0]. Real packet data was displaced by the same\namount and truncated at the end.\n\nSubtract the old data_len before replacing it and add the new data_len\nafterwards, keeping skb-\u003elen and skb-\u003edata_len synchronized.\n\nAdditionally, bpf_xdp_pull_data() can advance data_end while leaving\nfrags present. The skb is then still non-linear, so the old\n__skb_put(skb, off) triggers SKB_LINEAR_ASSERT().\n\nUse skb_set_tail_pointer() and update skb-\u003elen explicitly instead,\nfollowing bpf_prog_run_generic_xdp(). Unlike __skb_put(),\nskb_set_tail_pointer() does not require a linear skb.\n\nA 60000-byte UDP datagram on a veth pair with MTU 64000 was shortened by\n1024 bytes from its fragment area. Before the fix, all 10 runs produced\ncorrupted payloads. After the fix, all 10 runs matched the expected\npayload exactly. A forced-tailroom reproducer also exercises\nbpf_xdp_pull_data() with frags still present; the old code triggers\nSKB_LINEAR_ASSERT(), while this fix passes 10/10 runs."
    }
  ],
  "id": "CVE-2026-74612",
  "lastModified": "2026-08-25T06:18:38.680",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 10.0,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 6.0,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-22T16:16:33.770",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0c3024afabb8064b141f3cedcb1ddd6ab05ad9d5"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2f2a7f3f8b9f1bffc9b0488aa02b6951b2aec139"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3205b0652a37255dbb7ca8f3d942c8d8aa677c21"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/41b96667d42b74bb4b137f1bb78b611a953c5943"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/cb6379feaaff11c4e1e79c26c745ffa23182768a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/cdf745b7a777f87f51666e5d8f4c6fc279bcf54d"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

GHSA-PG5F-GW23-248R

Vulnerability from github – Published: 2026-08-22 18:30 – Updated: 2026-08-25 06:31

Details

In the Linux kernel, the following vulnerability has been resolved:

veth: fix skb length accounting after XDP frag adjustment

veth exposes non-linear skb fragments through an xdp_buff. If an XDP program adjusts the fragment area, veth_xdp_rcv_skb() copies xdp_frags_size back to skb->data_len but leaves skb->len containing the old fragment contribution.

After a fragment shrink, this makes skb_headlen() larger than the actual linear area. In the reproduced UDP receive path, __skb_datagram_iter() copied 1024 bytes past the actual linear tail to userspace, starting at struct skb_shared_info. The copied bytes included the affected skb's nr_frags, xdp_frags_size, and a kernel pointer from skb_shinfo(skb)->frags[0]. Real packet data was displaced by the same amount and truncated at the end.

Subtract the old data_len before replacing it and add the new data_len afterwards, keeping skb->len and skb->data_len synchronized.

Additionally, bpf_xdp_pull_data() can advance data_end while leaving frags present. The skb is then still non-linear, so the old __skb_put(skb, off) triggers SKB_LINEAR_ASSERT().

Use skb_set_tail_pointer() and update skb->len explicitly instead, following bpf_prog_run_generic_xdp(). Unlike __skb_put(), skb_set_tail_pointer() does not require a linear skb.

A 60000-byte UDP datagram on a veth pair with MTU 64000 was shortened by 1024 bytes from its fragment area. Before the fix, all 10 runs produced corrupted payloads. After the fix, all 10 runs matched the expected payload exactly. A forced-tailroom reproducer also exercises bpf_xdp_pull_data() with frags still present; the old code triggers SKB_LINEAR_ASSERT(), while this fix passes 10/10 runs.

Severity

10.0 (Critical)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-74612"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-22T16:16:33Z",
    "severity": "CRITICAL"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nveth: fix skb length accounting after XDP frag adjustment\n\nveth exposes non-linear skb fragments through an xdp_buff. If an XDP\nprogram adjusts the fragment area, veth_xdp_rcv_skb() copies\nxdp_frags_size back to skb-\u003edata_len but leaves skb-\u003elen containing the\nold fragment contribution.\n\nAfter a fragment shrink, this makes skb_headlen() larger than the actual\nlinear area. In the reproduced UDP receive path, __skb_datagram_iter()\ncopied 1024 bytes past the actual linear tail to userspace, starting at\nstruct skb_shared_info. The copied bytes included the affected skb\u0027s\nnr_frags, xdp_frags_size, and a kernel pointer from\nskb_shinfo(skb)-\u003efrags[0]. Real packet data was displaced by the same\namount and truncated at the end.\n\nSubtract the old data_len before replacing it and add the new data_len\nafterwards, keeping skb-\u003elen and skb-\u003edata_len synchronized.\n\nAdditionally, bpf_xdp_pull_data() can advance data_end while leaving\nfrags present. The skb is then still non-linear, so the old\n__skb_put(skb, off) triggers SKB_LINEAR_ASSERT().\n\nUse skb_set_tail_pointer() and update skb-\u003elen explicitly instead,\nfollowing bpf_prog_run_generic_xdp(). Unlike __skb_put(),\nskb_set_tail_pointer() does not require a linear skb.\n\nA 60000-byte UDP datagram on a veth pair with MTU 64000 was shortened by\n1024 bytes from its fragment area. Before the fix, all 10 runs produced\ncorrupted payloads. After the fix, all 10 runs matched the expected\npayload exactly. A forced-tailroom reproducer also exercises\nbpf_xdp_pull_data() with frags still present; the old code triggers\nSKB_LINEAR_ASSERT(), while this fix passes 10/10 runs.",
  "id": "GHSA-pg5f-gw23-248r",
  "modified": "2026-08-25T06:31:22Z",
  "published": "2026-08-22T18:30:26Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74612"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0c3024afabb8064b141f3cedcb1ddd6ab05ad9d5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2f2a7f3f8b9f1bffc9b0488aa02b6951b2aec139"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3205b0652a37255dbb7ca8f3d942c8d8aa677c21"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/41b96667d42b74bb4b137f1bb78b611a953c5943"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cb6379feaaff11c4e1e79c26c745ffa23182768a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cdf745b7a777f87f51666e5d8f4c6fc279bcf54d"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

MSRC_CVE-2026-74612

Vulnerability from csaf_microsoft - Published: 2026-08-24 01:01 - Updated: 2026-08-24 14:45

Summary

veth: fix skb length accounting after XDP frag adjustment

Notes

Additional Resources: To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle

Disclaimer: The information provided in the Microsoft Knowledge Base is provided \"as is\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

CVE-2026-74612

Affected products

Known affected 1 product

Product	Identifier	Version	Remediation
Unresolved product id: 17084-1		—	None Available

References

4 references

URL	Category
https://msrc.microsoft.com/csaf/vex/2026/msrc_cve…	self
https://support.microsoft.com/lifecycle	external
https://www.first.org/cvss	external
https://msrc.microsoft.com/csaf/vex/2026/msrc_cve…	self

JSON

To clipboard

{
  "document": {
    "category": "csaf_vex",
    "csaf_version": "2.0",
    "distribution": {
      "text": "Public",
      "tlp": {
        "label": "WHITE",
        "url": "https://www.first.org/tlp/"
      }
    },
    "lang": "en-US",
    "notes": [
      {
        "category": "general",
        "text": "To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle",
        "title": "Additional Resources"
      },
      {
        "category": "legal_disclaimer",
        "text": "The information provided in the Microsoft Knowledge Base is provided \\\"as is\\\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.",
        "title": "Disclaimer"
      }
    ],
    "publisher": {
      "category": "vendor",
      "contact_details": "secure@microsoft.com",
      "name": "Microsoft Security Response Center",
      "namespace": "https://msrc.microsoft.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "CVE-2026-74612 veth: fix skb length accounting after XDP frag adjustment - VEX",
        "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-74612.json"
      },
      {
        "category": "external",
        "summary": "Microsoft Support Lifecycle",
        "url": "https://support.microsoft.com/lifecycle"
      },
      {
        "category": "external",
        "summary": "Common Vulnerability Scoring System",
        "url": "https://www.first.org/cvss"
      }
    ],
    "title": "veth: fix skb length accounting after XDP frag adjustment",
    "tracking": {
      "current_release_date": "2026-08-24T14:45:13.000Z",
      "generator": {
        "date": "2026-08-25T07:02:58.268Z",
        "engine": {
          "name": "MSRC Generator",
          "version": "1.0"
        }
      },
      "id": "msrc_CVE-2026-74612",
      "initial_release_date": "2026-08-24T01:01:44.000Z",
      "revision_history": [
        {
          "date": "2026-08-24T01:01:44.000Z",
          "legacy_version": "1",
          "number": "1",
          "summary": "Information published."
        },
        {
          "date": "2026-08-24T14:45:13.000Z",
          "legacy_version": "2",
          "number": "2",
          "summary": "Information published."
        }
      ],
      "status": "final",
      "version": "2"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version",
                "name": "3.0",
                "product": {
                  "name": "Azure Linux 3.0",
                  "product_id": "17084"
                }
              }
            ],
            "category": "product_name",
            "name": "Azure Linux"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "azl3 kernel 0:6.6.150.1-1.azl3",
                "product": {
                  "name": "azl3 kernel 0:6.6.150.1-1.azl3",
                  "product_id": "1"
                }
              }
            ],
            "category": "product_name",
            "name": "kernel"
          }
        ],
        "category": "vendor",
        "name": "Microsoft"
      }
    ],
    "relationships": [
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "azl3 kernel 0:6.6.150.1-1.azl3 as a component of Azure Linux 3.0",
          "product_id": "17084-1"
        },
        "product_reference": "1",
        "relates_to_product_reference": "17084"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2026-74612",
      "notes": [
        {
          "category": "general",
          "text": "Linux",
          "title": "Assigning CNA"
        }
      ],
      "product_status": {
        "known_affected": [
          "17084-1"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2026-74612 veth: fix skb length accounting after XDP frag adjustment - VEX",
          "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-74612.json"
        }
      ],
      "remediations": [
        {
          "category": "none_available",
          "date": "2026-08-24T01:01:44.000Z",
          "details": "There is no fix available for this vulnerability as of now",
          "product_ids": [
            "17084-1"
          ]
        }
      ],
      "title": "veth: fix skb length accounting after XDP frag adjustment"
    }
  ]
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

CVE-2026-74612 (GCVE-0-2026-74612)

FKIE_CVE-2026-74612

GHSA-PG5F-GW23-248R

MSRC_CVE-2026-74612

Tags

Sightings

Nomenclature