SEPTEMBER 13, 2026
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Case File

CVE-2026-89643

CRITICAL · CVSS 9.8 EPSS 0.63%

Source: NVD + CISA KEV + EPSS · Published 2026-09-11 · Last synced 2026-09-13

CyberRota Analysis

AI-Generated

The vulnerability affects the Linux kernel's audit subsystem, specifically in the handling of fsnotify rules during the deletion process. An improper reference management can lead to a use-after-free condition, potentially allowing an attacker to dereference freed memory, which may result in system instability or exploitation. Organizations using affected Linux kernel versions should prioritize patching this vulnerability to maintain system integrity and security.

CVE
CVE-2026-89643
Severity
CRITICAL
CVSS
9.8
EPSS
0.63%
Linux

Original NVD 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]