Bug 2532025 (CVE-2026-89643)

Summary: CVE-2026-89643 kernel: audit: avoid dropping live tree ref on fsnotify rule autoremove
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in the Linux kernel's audit subsystem. When `fsnotify` rules are automatically removed, the system incorrectly manages memory references, leading to a situation where freed memory can be accessed again. This memory corruption vulnerability could allow a local attacker to cause a system crash, leading to a denial of service.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-09-11 20:03:48 UTC 
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]
Comment 1 Mauro Matteo Cascella 2026-09-14 09:04:18 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89643.mbox