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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-68284
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-10 13:20:17 UTC
Updated2026-08-10 13:20:17 UTC
DescriptionIn 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.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 604326b41a6fb9b4a78b6179335decee0365cd8c ee762f684eefa59de34d9ed93cab08336e834f47 git Not specified
CNA Linux Linux affected 604326b41a6fb9b4a78b6179335decee0365cd8c cde4d6bcd9b73073c66498f6723c7b364c4dbc18 git Not specified
CNA Linux Linux affected 604326b41a6fb9b4a78b6179335decee0365cd8c 786d690257ec7a0c839f8710456e444ce3f1348b git Not specified
CNA Linux Linux affected 604326b41a6fb9b4a78b6179335decee0365cd8c 752b1159ed5d0c48fe169a3721b96660a9822aa1 git Not specified
CNA Linux Linux affected 604326b41a6fb9b4a78b6179335decee0365cd8c 2d66a033864e27ab8d5e44cb36f31d9d2413bee4 git Not specified
CNA Linux Linux affected 4.20 Not specified
CNA Linux Linux unaffected 4.20 semver Not specified
CNA Linux Linux unaffected 6.6.148 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.101 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.42 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.6 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2-rc5 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/ee762f684eefa59de34d9ed93cab08336e834f47 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/2d66a033864e27ab8d5e44cb36f31d9d2413bee4 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/786d690257ec7a0c839f8710456e444ce3f1348b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/752b1159ed5d0c48fe169a3721b96660a9822aa1 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/cde4d6bcd9b73073c66498f6723c7b364c4dbc18 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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