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VulnerabilityPublished Updated

CVE-2026-68284: Linux kernel · bpf, sockmap: Fix cork use-after-free in tcp_bpf_sendmsg()

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in ee762f684eefa59de34d9ed93cab08336e834f47 : patch Linux kernel soon.

Data as of 26 Oct 2026, 13:47 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in ee762f684eefa59de34d9ed93cab08336e834f47, cde4d6bcd9b73073c66498f6723c7b364c4dbc18, b2bcbeabfd843d47468fa095b1bd08ddb90cf616 +5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 10 Aug 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 604326b41a6fb9b4a78b6179335decee0365cd8c, < ee762f684eefa59de34d9ed93cab08336e834f47
Fixed in
  • ee762f684eefa59de34d9ed93cab08336e834f47
LinuxLinuxAffected
  • ≥ 604326b41a6fb9b4a78b6179335decee0365cd8c, < cde4d6bcd9b73073c66498f6723c7b364c4dbc18
Fixed in
  • cde4d6bcd9b73073c66498f6723c7b364c4dbc18
LinuxLinuxAffected
  • ≥ 604326b41a6fb9b4a78b6179335decee0365cd8c, < b2bcbeabfd843d47468fa095b1bd08ddb90cf616
Fixed in
  • b2bcbeabfd843d47468fa095b1bd08ddb90cf616
LinuxLinuxAffected
  • ≥ 604326b41a6fb9b4a78b6179335decee0365cd8c, < 786d690257ec7a0c839f8710456e444ce3f1348b
Fixed in
  • 786d690257ec7a0c839f8710456e444ce3f1348b
LinuxLinuxAffected
  • ≥ 604326b41a6fb9b4a78b6179335decee0365cd8c, < 752b1159ed5d0c48fe169a3721b96660a9822aa1
Fixed in
  • 752b1159ed5d0c48fe169a3721b96660a9822aa1
LinuxLinuxAffected
  • ≥ 604326b41a6fb9b4a78b6179335decee0365cd8c, < 0688e6fe599d2d39147ae9ece97944c6e1815ebf
Fixed in
  • 0688e6fe599d2d39147ae9ece97944c6e1815ebf

Description

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.

References

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