{"id":"CVE-2026-68284","title":"bpf, sockmap: Fix cork use-after-free in tcp_bpf_sendmsg()","summary":"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.  …","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 604326b41a6fb9b4a78b6179335decee0365cd8c < 0688e6fe599d2d39147ae9ece97944c6e1815ebf","Linux >= 604326b41a6fb9b4a78b6179335decee0365cd8c < b2bcbeabfd843d47468fa095b1bd08ddb90cf616","Linux >= 604326b41a6fb9b4a78b6179335decee0365cd8c < 54be47e7cbb936429c3bbdfc526ea943954aaf80","Linux >= 604326b41a6fb9b4a78b6179335decee0365cd8c < ee762f684eefa59de34d9ed93cab08336e834f47","Linux >= 604326b41a6fb9b4a78b6179335decee0365cd8c < cde4d6bcd9b73073c66498f6723c7b364c4dbc18","Linux >= 604326b41a6fb9b4a78b6179335decee0365cd8c < 786d690257ec7a0c839f8710456e444ce3f1348b","Linux >= 604326b41a6fb9b4a78b6179335decee0365cd8c < 752b1159ed5d0c48fe169a3721b96660a9822aa1","Linux >= 604326b41a6fb9b4a78b6179335decee0365cd8c < 2d66a033864e27ab8d5e44cb36f31d9d2413bee4","Linux 4.20"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-16T15:46:33.864710Z"},"published":"2026-08-10","updated":"2026-10-16","sourceUpdated":"2026-10-16T15:53:06.141Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-68284","references":[{"url":"https://git.kernel.org/stable/c/0688e6fe599d2d39147ae9ece97944c6e1815ebf"},{"url":"https://git.kernel.org/stable/c/b2bcbeabfd843d47468fa095b1bd08ddb90cf616"},{"url":"https://git.kernel.org/stable/c/54be47e7cbb936429c3bbdfc526ea943954aaf80"},{"url":"https://git.kernel.org/stable/c/ee762f684eefa59de34d9ed93cab08336e834f47"},{"url":"https://git.kernel.org/stable/c/cde4d6bcd9b73073c66498f6723c7b364c4dbc18"},{"url":"https://git.kernel.org/stable/c/786d690257ec7a0c839f8710456e444ce3f1348b"},{"url":"https://git.kernel.org/stable/c/752b1159ed5d0c48fe169a3721b96660a9822aa1"},{"url":"https://git.kernel.org/stable/c/2d66a033864e27ab8d5e44cb36f31d9d2413bee4"}],"tags":["cve.org"],"epss":0.00135,"epssPercentile":0.02627,"ingestedAt":"2026-10-16T17:24:46.853Z","slug":"CVE-2026-68284","body":"## Overview\n\nIn 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->cork.\n\nThis comparison is unsafe when two threads send on the same socket:\n\n  Thread A                         Thread B\n  msg_tx = psock->cork\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->cork = NULL\n                                  frees the cork\n    reacquires the socket lock\n  msg_tx != psock->cork\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->cork cannot turn a shared message into\nan apparent local one.\n\n## Affected\n\n- `Linux >= 604326b41a6fb9b4a78b6179335decee0365cd8c < 0688e6fe599d2d39147ae9ece97944c6e1815ebf`\n- `Linux >= 604326b41a6fb9b4a78b6179335decee0365cd8c < b2bcbeabfd843d47468fa095b1bd08ddb90cf616`\n- `Linux >= 604326b41a6fb9b4a78b6179335decee0365cd8c < 54be47e7cbb936429c3bbdfc526ea943954aaf80`\n- `Linux >= 604326b41a6fb9b4a78b6179335decee0365cd8c < ee762f684eefa59de34d9ed93cab08336e834f47`\n- `Linux >= 604326b41a6fb9b4a78b6179335decee0365cd8c < cde4d6bcd9b73073c66498f6723c7b364c4dbc18`\n- `Linux >= 604326b41a6fb9b4a78b6179335decee0365cd8c < 786d690257ec7a0c839f8710456e444ce3f1348b`\n- `Linux >= 604326b41a6fb9b4a78b6179335decee0365cd8c < 752b1159ed5d0c48fe169a3721b96660a9822aa1`\n- `Linux >= 604326b41a6fb9b4a78b6179335decee0365cd8c < 2d66a033864e27ab8d5e44cb36f31d9d2413bee4`\n- `Linux 4.20`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}