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

Vulnerability from cvelistv5 – Published: 2026-08-10 12:02 – Updated: 2026-08-10 12:02
VLAI
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
References
Impacted 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)
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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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{
  "containers": {
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      "affected": [
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          "product": "Linux",
          "programFiles": [
            "net/ipv4/tcp_bpf.c"
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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": [
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          "url": "https://git.kernel.org/stable/c/ee762f684eefa59de34d9ed93cab08336e834f47"
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        },
        {
          "url": "https://git.kernel.org/stable/c/2d66a033864e27ab8d5e44cb36f31d9d2413bee4"
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      "title": "bpf, sockmap: Fix cork use-after-free in tcp_bpf_sendmsg()",
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    "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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    "nvd": "{\"cve\":{\"id\":\"CVE-2026-68284\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-08-10T13:20:17.670\",\"lastModified\":\"2026-08-10T13:20:17.670\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"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.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"net/ipv4/tcp_bpf.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"604326b41a6fb9b4a78b6179335decee0365cd8c\",\"lessThan\":\"ee762f684eefa59de34d9ed93cab08336e834f47\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"604326b41a6fb9b4a78b6179335decee0365cd8c\",\"lessThan\":\"cde4d6bcd9b73073c66498f6723c7b364c4dbc18\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"604326b41a6fb9b4a78b6179335decee0365cd8c\",\"lessThan\":\"786d690257ec7a0c839f8710456e444ce3f1348b\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"604326b41a6fb9b4a78b6179335decee0365cd8c\",\"lessThan\":\"752b1159ed5d0c48fe169a3721b96660a9822aa1\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"604326b41a6fb9b4a78b6179335decee0365cd8c\",\"lessThan\":\"2d66a033864e27ab8d5e44cb36f31d9d2413bee4\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"net/ipv4/tcp_bpf.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"4.20\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"4.20\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.148\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.101\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.42\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.6\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2-rc5\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/2d66a033864e27ab8d5e44cb36f31d9d2413bee4\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/752b1159ed5d0c48fe169a3721b96660a9822aa1\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/786d690257ec7a0c839f8710456e444ce3f1348b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/cde4d6bcd9b73073c66498f6723c7b364c4dbc18\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/ee762f684eefa59de34d9ed93cab08336e834f47\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Important",
      "current_release_date": "2026-08-11T17:41:05+00:00",
      "cve": "CVE-2026-68284",
      "id": "CVE-2026-68284",
      "initial_release_date": "2026-08-10T12:02:16.572000+00:00",
      "product_status:known_affected": "109",
      "product_status:known_not_affected": "167",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: Linux kernel: bpf/sockmap use-after-free vulnerability leading to denial of service",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-68284.json",
      "version": "3"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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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.