CVE-2026-89643: Linux Vulnerability (CVSS 9.8)

Description

In the Linux kernel, the following vulnerability has been resolved: audit: avoid dropping live tree ref on fsnotify rule autoremove audit_del_rule() is used for both netlink deletion templates and internal fsnotify autoremove. The former passes a parsed template which owns a temporary tree reference; the latter passes the installed entry itself. The unconditional audit_put_tree() at the end of audit_del_rule() assumes the template case. For mixed AUDIT_DIR plus AUDIT_EXE rules, an fsnotify autoremove event therefore drops the installed rule's live tree reference. Repeating this across rules sharing the same tree can free the tree while another rule still references it, and a later autoremove dereferences the freed pathname while comparing rules. Move the temporary-tree put to audit_rule_change(), the caller that owns deletion templates. Keep it in the AUDIT_DEL_RULE cleanup so both successful deletion and -ENOENT still release the parser-owned tree. [PM: dropped unnecessary comment for line length reasons]

Metrics

CVSS 3.1

9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.63%

48.1th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= 34d99af52ad40bd498ba66970579a5bc1fb1a3bc, < 9cac21f8eb82675ed19fb955b8bbb9dd14cc3d58; >= 34d99af52ad40bd498ba66970579a5bc1fb1a3bc, < b322cc7adcd2e6ec1594d187533a126506ab545c; >= 34d99af52ad40bd498ba66970579a5bc1fb1a3bc, < 695c85dc345a4e0292739f004c261bedef3f27e6; >= 34d99af52ad40bd498ba66970579a5bc1fb1a3bc, < 01b0ec8c397be65ff710777c97017ca1de56ef8e; >= 34d99af52ad40bd498ba66970579a5bc1fb1a3bc, < cf37b61b5420fd4600fe78cf8c24da6e4d9bfe28; >= 34d99af52ad40bd498ba66970579a5bc1fb1a3bc, < 636a99bab36ba27515363d325866c0273ac83b3e; >= 34d99af52ad40bd498ba66970579a5bc1fb1a3bc, < 583cf579b32d99e3fe4e9c8ecc4d852e3708fbec; >= 34d99af52ad40bd498ba66970579a5bc1fb1a3bc, < 783f0f0974c156aca630f4ffff248671082a098d
Linux	Linux	4.3

References

Timeline

Published: Sep 11, 2026
Last Modified: Sep 14, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-89643?

In the Linux kernel, the following vulnerability has been resolved: audit: avoid dropping live tree ref on fsnotify rule autoremove audit_del_rule() is used for both netlink deletion templates and internal fsnotify autoremove. The former passes a parsed template which owns a temporary tree reference; the latter passes the installed entry itself. The unconditional audit_put_tree() at the end of audit_del_rule() assumes the template case. For mixed AUDIT_DIR plus AUDIT_EXE rules, an fsnotify autoremove event therefore drops the installed rule's live tree reference. Repeating this across rules sharing the same tree can free the tree while another rule still references it, and a later autoremove dereferences the freed pathname while comparing rules. Move the temporary-tree put to audit_rule_change(), the caller that owns deletion templates. Keep it in the AUDIT_DEL_RULE cleanup so both successful deletion and -ENOENT still release the parser-owned tree. [PM: dropped unnecessary comment for line length reasons]

How severe is CVE-2026-89643?

CVE-2026-89643 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 0.63% probability of exploitation in the next 30 days.

How do I fix CVE-2026-89643?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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