Vulnerability-Lookup

GHSA-F87H-88F3-M92W

Vulnerability from github – Published: 2026-08-10 15:33 – Updated: 2026-08-10 15:33

Details

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

bpf, sockmap: Fix cork use-after-free in tcp_bpf_sendmsg()

tcp_bpf_sendmsg() keeps msg_tx across sk_stream_wait_memory(), which drops and reacquires the socket lock. Its error path tries to decide whether msg_tx names the local temporary message by comparing it with the current value of psock->cork.

This comparison is unsafe when two threads send on the same socket:

Thread A Thread B msg_tx = psock->cork sk_msg_alloc() fails sk_stream_wait_memory() releases the socket lock acquires the socket lock completes the cork psock->cork = NULL frees the cork reacquires the socket lock msg_tx != psock->cork sk_msg_free(msg_tx)

The stale cork is therefore mistaken for the local temporary message and freed again. KASAN reported:

BUG: KASAN: slab-use-after-free in sk_msg_free+0x49/0x50 Read of size 4 at addr ffff88810c908800 by task poc/90 Call Trace: sk_msg_free+0x49/0x50 tcp_bpf_sendmsg+0x14f5/0x1cc0 __sys_sendto+0x32c/0x3a0 __x64_sys_sendto+0xdb/0x1b0 Allocated by task 89: __kasan_kmalloc+0x8f/0xa0 tcp_bpf_sendmsg+0x16b3/0x1cc0 Freed by task 91: __kasan_slab_free+0x43/0x70 kfree+0x131/0x3c0 tcp_bpf_sendmsg+0xec3/0x1cc0

msg_tx can only name the stack-local tmp or the shared cork. Check for tmp directly so a changed psock->cork cannot turn a shared message into an apparent local one.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-68284"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-10T13:20:17Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf, sockmap: Fix cork use-after-free in tcp_bpf_sendmsg()\n\ntcp_bpf_sendmsg() keeps msg_tx across sk_stream_wait_memory(), which\ndrops and reacquires the socket lock.  Its error path tries to decide\nwhether msg_tx names the local temporary message by comparing it with\nthe current value of psock-\u003ecork.\n\nThis comparison is unsafe when two threads send on the same socket:\n\n  Thread A                         Thread B\n  msg_tx = psock-\u003ecork\n  sk_msg_alloc() fails\n  sk_stream_wait_memory()\n    releases the socket lock      acquires the socket lock\n                                  completes the cork\n                                  psock-\u003ecork = NULL\n                                  frees the cork\n    reacquires the socket lock\n  msg_tx != psock-\u003ecork\n  sk_msg_free(msg_tx)\n\nThe stale cork is therefore mistaken for the local temporary message\nand freed again.  KASAN reported:\n\n  BUG: KASAN: slab-use-after-free in sk_msg_free+0x49/0x50\n  Read of size 4 at addr ffff88810c908800 by task poc/90\n  Call Trace:\n   sk_msg_free+0x49/0x50\n   tcp_bpf_sendmsg+0x14f5/0x1cc0\n   __sys_sendto+0x32c/0x3a0\n   __x64_sys_sendto+0xdb/0x1b0\n  Allocated by task 89:\n   __kasan_kmalloc+0x8f/0xa0\n   tcp_bpf_sendmsg+0x16b3/0x1cc0\n  Freed by task 91:\n   __kasan_slab_free+0x43/0x70\n   kfree+0x131/0x3c0\n   tcp_bpf_sendmsg+0xec3/0x1cc0\n\nmsg_tx can only name the stack-local tmp or the shared cork. Check for\ntmp directly so a changed psock-\u003ecork cannot turn a shared message into\nan apparent local one.",
  "id": "GHSA-f87h-88f3-m92w",
  "modified": "2026-08-10T15:33:44Z",
  "published": "2026-08-10T15:33:44Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-68284"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2d66a033864e27ab8d5e44cb36f31d9d2413bee4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/752b1159ed5d0c48fe169a3721b96660a9822aa1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/786d690257ec7a0c839f8710456e444ce3f1348b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cde4d6bcd9b73073c66498f6723c7b364c4dbc18"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ee762f684eefa59de34d9ed93cab08336e834f47"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-68284 (GCVE-0-2026-68284)

Vulnerability from cvelistv5 – Published: 2026-08-10 12:02 – Updated: 2026-08-10 12:02

Title

bpf, sockmap: Fix cork use-after-free in tcp_bpf_sendmsg()

Summary

In the Linux kernel, the following vulnerability has been resolved: bpf, sockmap: Fix cork use-after-free in tcp_bpf_sendmsg() tcp_bpf_sendmsg() keeps msg_tx across sk_stream_wait_memory(), which drops and reacquires the socket lock. Its error path tries to decide whether msg_tx names the local temporary message by comparing it with the current value of psock->cork. This comparison is unsafe when two threads send on the same socket: Thread A Thread B msg_tx = psock->cork sk_msg_alloc() fails sk_stream_wait_memory() releases the socket lock acquires the socket lock completes the cork psock->cork = NULL frees the cork reacquires the socket lock msg_tx != psock->cork sk_msg_free(msg_tx) The stale cork is therefore mistaken for the local temporary message and freed again. KASAN reported: BUG: KASAN: slab-use-after-free in sk_msg_free+0x49/0x50 Read of size 4 at addr ffff88810c908800 by task poc/90 Call Trace: sk_msg_free+0x49/0x50 tcp_bpf_sendmsg+0x14f5/0x1cc0 __sys_sendto+0x32c/0x3a0 __x64_sys_sendto+0xdb/0x1b0 Allocated by task 89: __kasan_kmalloc+0x8f/0xa0 tcp_bpf_sendmsg+0x16b3/0x1cc0 Freed by task 91: __kasan_slab_free+0x43/0x70 kfree+0x131/0x3c0 tcp_bpf_sendmsg+0xec3/0x1cc0 msg_tx can only name the stack-local tmp or the shared cork. Check for tmp directly so a changed psock->cork cannot turn a shared message into an apparent local one.

Severity

No CVSS data available.

Assigner

Linux

References

5 references

URL	Tags
https://git.kernel.org/stable/c/ee762f684eefa59de…
https://git.kernel.org/stable/c/cde4d6bcd9b73073c…
https://git.kernel.org/stable/c/786d690257ec7a0c8…
https://git.kernel.org/stable/c/752b1159ed5d0c48f…
https://git.kernel.org/stable/c/2d66a033864e27ab8…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 604326b41a6fb9b4a78b6179335decee0365cd8c , < ee762f684eefa59de34d9ed93cab08336e834f47 (git) Affected: 604326b41a6fb9b4a78b6179335decee0365cd8c , < cde4d6bcd9b73073c66498f6723c7b364c4dbc18 (git) Affected: 604326b41a6fb9b4a78b6179335decee0365cd8c , < 786d690257ec7a0c839f8710456e444ce3f1348b (git) Affected: 604326b41a6fb9b4a78b6179335decee0365cd8c , < 752b1159ed5d0c48fe169a3721b96660a9822aa1 (git) Affected: 604326b41a6fb9b4a78b6179335decee0365cd8c , < 2d66a033864e27ab8d5e44cb36f31d9d2413bee4 (git)
Linux	Linux	Affected: 4.20 Unaffected: 0 , < 4.20 (semver) Unaffected: 6.6.148 , ≤ 6.6.* (semver) Unaffected: 6.12.101 , ≤ 6.12.* (semver) Unaffected: 6.18.42 , ≤ 6.18.* (semver) Unaffected: 7.1.6 , ≤ 7.1.* (semver) Unaffected: 7.2-rc5 , ≤ * (original_commit_for_fix)

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          "programFiles": [
            "net/ipv4/tcp_bpf.c"
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          "vendor": "Linux",
          "versions": [
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              "lessThan": "ee762f684eefa59de34d9ed93cab08336e834f47",
              "status": "affected",
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              "versionType": "git"
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              "lessThan": "cde4d6bcd9b73073c66498f6723c7b364c4dbc18",
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          "product": "Linux",
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
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              "version": "4.20"
            },
            {
              "lessThan": "4.20",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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              "versionType": "semver"
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              "status": "unaffected",
              "version": "6.12.101",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.42",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2-rc5",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf, sockmap: Fix cork use-after-free in tcp_bpf_sendmsg()\n\ntcp_bpf_sendmsg() keeps msg_tx across sk_stream_wait_memory(), which\ndrops and reacquires the socket lock.  Its error path tries to decide\nwhether msg_tx names the local temporary message by comparing it with\nthe current value of psock-\u003ecork.\n\nThis comparison is unsafe when two threads send on the same socket:\n\n  Thread A                         Thread B\n  msg_tx = psock-\u003ecork\n  sk_msg_alloc() fails\n  sk_stream_wait_memory()\n    releases the socket lock      acquires the socket lock\n                                  completes the cork\n                                  psock-\u003ecork = NULL\n                                  frees the cork\n    reacquires the socket lock\n  msg_tx != psock-\u003ecork\n  sk_msg_free(msg_tx)\n\nThe stale cork is therefore mistaken for the local temporary message\nand freed again.  KASAN reported:\n\n  BUG: KASAN: slab-use-after-free in sk_msg_free+0x49/0x50\n  Read of size 4 at addr ffff88810c908800 by task poc/90\n  Call Trace:\n   sk_msg_free+0x49/0x50\n   tcp_bpf_sendmsg+0x14f5/0x1cc0\n   __sys_sendto+0x32c/0x3a0\n   __x64_sys_sendto+0xdb/0x1b0\n  Allocated by task 89:\n   __kasan_kmalloc+0x8f/0xa0\n   tcp_bpf_sendmsg+0x16b3/0x1cc0\n  Freed by task 91:\n   __kasan_slab_free+0x43/0x70\n   kfree+0x131/0x3c0\n   tcp_bpf_sendmsg+0xec3/0x1cc0\n\nmsg_tx can only name the stack-local tmp or the shared cork. Check for\ntmp directly so a changed psock-\u003ecork cannot turn a shared message into\nan apparent local one."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-10T12:02:16.572Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/ee762f684eefa59de34d9ed93cab08336e834f47"
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        },
        {
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        },
        {
          "url": "https://git.kernel.org/stable/c/2d66a033864e27ab8d5e44cb36f31d9d2413bee4"
        }
      ],
      "title": "bpf, sockmap: Fix cork use-after-free in tcp_bpf_sendmsg()",
      "x_generator": {
        "engine": "bippy-1.2.0"
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    }
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-68284",
    "datePublished": "2026-08-10T12:02:16.572Z",
    "dateReserved": "2026-07-30T09:28:09.379Z",
    "dateUpdated": "2026-08-10T12:02:16.572Z",
    "state": "PUBLISHED"
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  "dataVersion": "5.2"
}

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.

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GHSA-F87H-88F3-M92W

CVE-2026-68284 (GCVE-0-2026-68284)

Tags

Sightings

Nomenclature