CyberSecBulletin
CVE-2026-43076NVD status: Modified

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2026-43076 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 unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists versions d012c782abcabe68b5b9e71be58a15e9f9d83dc1, bcd46bc261b215b3b12c557a978299eafa02ecdd, 131c0b573e1b467b7d553e9ff38003f1acd8f5f2 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 0.13% 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 d012c782abcabe68b5b9e71be58a15e9f9d83dc1 or bcd46bc261b215b3b12c557a978299eafa02ecdd or 131c0b573e1b467b7d553e9ff38003f1acd8f5f2 or 37f074e65f24f10f8d8df224a572e4cb9e6faf63, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.6.136 or 6.12.83 or 6.18.24 or 6.19.14, whichever matches your release line, or a later version.
  3. Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux23193e513d1cd69411469f028d56fd175d4a6b07 up to, but not including, d012c782abcabe68b5b9e71be58a15e9f9d83dc1; 23193e513d1cd69411469f028d56fd175d4a6b07 up to, but not including, bcd46bc261b215b3b12c557a978299eafa02ecdd; 23193e513d1cd69411469f028d56fd175d4a6b07 up to, but not including, 131c0b573e1b467b7d553e9ff38003f1acd8f5f2; 23193e513d1cd69411469f028d56fd175d4a6b07 up to, but not including, 37f074e65f24f10f8d8df224a572e4cb9e6faf63; 23193e513d1cd69411469f028d56fd175d4a6b07 up to, but not including, c1de19e891be3bfb3e1d0c7cf07bbb8fb3b77c1b; 23193e513d1cd69411469f028d56fd175d4a6b07 up to, but not including, cd2d765aa7157f852999842af32148128c735d39; 23193e513d1cd69411469f028d56fd175d4a6b07 up to, but not including, 77d0295725109d77f5854ef5b58c0d06c08168cc; 23193e513d1cd69411469f028d56fd175d4a6b07 up to, but not including, 1524af3685b35feac76662cc551cbc37bd14775f; and 1 more rangesd012c782abcabe68b5b9e71be58a15e9f9d83dc1, bcd46bc261b215b3b12c557a978299eafa02ecdd, 131c0b573e1b467b7d553e9ff38003f1acd8f5f2, 37f074e65f24f10f8d8df224a572e4cb9e6faf63, c1de19e891be3bfb3e1d0c7cf07bbb8fb3b77c1b, cd2d765aa7157f852999842af32148128c735d39
LinuxLinux Kernel2.6.24.1 up to, but not including, 6.6.136; 6.7 up to, but not including, 6.12.83; 6.13 up to, but not including, 6.18.24; 6.19 up to, but not including, 6.19.14; 2.6.24; 7.06.6.136, 6.12.83, 6.18.24, 6.19.14

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
NoneNo account or login is needed.
User interaction
RequiredA user must take an action such as opening a file or link.
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:N/UI:R/S:U/C:H/I:H/A:H. Scored by CNA.

Official description

In the Linux kernel, the following vulnerability has been resolved: ocfs2: validate inline data i_size during inode read When reading an inode from disk, ocfs2_validate_inode_block() performs various sanity checks but does not validate the size of inline data. If the filesystem is corrupted, an inode's i_size can exceed the actual inline data capacity (id_count). This causes ocfs2_dir_foreach_blk_id() to iterate beyond the inline data buffer, triggering a use-after-free when accessing directory entries from freed memory. In the syzbot report: - i_size was 1099511627576 bytes (~1TB) - Actual inline data capacity (id_count) is typically <256 bytes - A garbage rec_len (54648) caused ctx->pos to jump out of bounds - This triggered a UAF in ocfs2_check_dir_entry() Fix by adding a validation check in ocfs2_validate_inode_block() to ensure inodes with inline data have i_size <= id_count. This catches the corruption early during inode read and prevents all downstream code from operating on invalid data.

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. Record last changed materially (score, affected products, status or references).

References

Recent Use After Free vulnerabilities

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