Linux: Use After Free
CVE-2026-23223 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 1d411278dda293a507cb794db7d9ed3511c685c6, ed82e7949f5cac3058f4100f3cd670531d41a266, ba5264610423d9653aa36920520902d83841bcfd 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.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 1d411278dda293a507cb794db7d9ed3511c685c6 or ed82e7949f5cac3058f4100f3cd670531d41a266 or ba5264610423d9653aa36920520902d83841bcfd or 1c253e11225bc5167217897885b85093e17c2217, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.12.72 or 6.18.11 or 6.19.1, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | ec793e690f801d97a7ae2a0d429fea1fee4d44aa up to, but not including, 1d411278dda293a507cb794db7d9ed3511c685c6; ec793e690f801d97a7ae2a0d429fea1fee4d44aa up to, but not including, ed82e7949f5cac3058f4100f3cd670531d41a266; ec793e690f801d97a7ae2a0d429fea1fee4d44aa up to, but not including, ba5264610423d9653aa36920520902d83841bcfd; ec793e690f801d97a7ae2a0d429fea1fee4d44aa up to, but not including, 1c253e11225bc5167217897885b85093e17c2217; 6.9 | 1d411278dda293a507cb794db7d9ed3511c685c6, ed82e7949f5cac3058f4100f3cd670531d41a266, ba5264610423d9653aa36920520902d83841bcfd, 1c253e11225bc5167217897885b85093e17c2217 |
| Linux | Linux Kernel | 6.9 up to, but not including, 6.12.72; 6.13 up to, but not including, 6.18.11; 6.19 up to, but not including, 6.19.1 | 6.12.72, 6.18.11, 6.19.1 |
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 NVD.
Official description
In the Linux kernel, the following vulnerability has been resolved: xfs: fix UAF in xchk_btree_check_block_owner We cannot dereference bs->cur when trying to determine if bs->cur aliases bs->sc->sa.{bno,rmap}_cur after the latter has been freed. Fix this by sampling before type before any freeing could happen. The correct temporal ordering was broken when we removed xfs_btnum_t.
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.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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