CyberSecBulletin
CVE-2026-68284NVD status: Received

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2026-68284 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 0688e6fe599d2d39147ae9ece97944c6e1815ebf, b2bcbeabfd843d47468fa095b1bd08ddb90cf616, 54be47e7cbb936429c3bbdfc526ea943954aaf80 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.14% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to 0688e6fe599d2d39147ae9ece97944c6e1815ebf or b2bcbeabfd843d47468fa095b1bd08ddb90cf616 or 54be47e7cbb936429c3bbdfc526ea943954aaf80 or ee762f684eefa59de34d9ed93cab08336e834f47, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux604326b41a6fb9b4a78b6179335decee0365cd8c up to, but not including, 0688e6fe599d2d39147ae9ece97944c6e1815ebf; 604326b41a6fb9b4a78b6179335decee0365cd8c up to, but not including, b2bcbeabfd843d47468fa095b1bd08ddb90cf616; 604326b41a6fb9b4a78b6179335decee0365cd8c up to, but not including, 54be47e7cbb936429c3bbdfc526ea943954aaf80; 604326b41a6fb9b4a78b6179335decee0365cd8c up to, but not including, ee762f684eefa59de34d9ed93cab08336e834f47; 604326b41a6fb9b4a78b6179335decee0365cd8c up to, but not including, cde4d6bcd9b73073c66498f6723c7b364c4dbc18; 604326b41a6fb9b4a78b6179335decee0365cd8c up to, but not including, 786d690257ec7a0c839f8710456e444ce3f1348b; 604326b41a6fb9b4a78b6179335decee0365cd8c up to, but not including, 752b1159ed5d0c48fe169a3721b96660a9822aa1; 604326b41a6fb9b4a78b6179335decee0365cd8c up to, but not including, 2d66a033864e27ab8d5e44cb36f31d9d2413bee4; and 1 more ranges0688e6fe599d2d39147ae9ece97944c6e1815ebf, b2bcbeabfd843d47468fa095b1bd08ddb90cf616, 54be47e7cbb936429c3bbdfc526ea943954aaf80, ee762f684eefa59de34d9ed93cab08336e834f47, cde4d6bcd9b73073c66498f6723c7b364c4dbc18, 786d690257ec7a0c839f8710456e444ce3f1348b

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.

Official 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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Use After Free

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.

How developers prevent this class of flaw

  • Choose a language that provides automatic memory management.
  • When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.

More Use After Free vulnerabilities (CWE-416)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Use After Free vulnerabilities

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