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CVE-2026-74512
audit: fix potential use-after-free in audit_del_rule()
Published 2026-08-15 (2 months ago) by the Linux kernel CNA. Subsystem kernel. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-74512 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | fixedDLA-4777-1 · 2026-09-08 · text | 6.1.187-1 | Update the kernel and reboot. DLA-4777-1 shipped the fix on 2026-09-08, in 6.1.187-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixedDSA-6466-1 · 2026-08-25 · text | 6.12.105-1 | Update the kernel and reboot. DSA-6466-1 shipped the fix on 2026-08-25, in 6.12.105-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.8-1 | Update the kernel and reboot. Fixed in 7.1.8-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.8-1 | Update the kernel and reboot. Fixed in 7.1.8-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4788-1 · 2026-09-19 · text | 6.12.107-1~deb12u1 | Update the kernel and reboot. DLA-4788-1 shipped the fix on 2026-09-19, in 6.12.107-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
`audit_del_rule()` destroys `e->rule.exe` via `audit_remove_mark_rule()` before unlinking the rule from RCU-visible filter lists and waiting for a grace period. Concurrent readers in `audit_filter()` and `audit_filter_rules()` still dereference `e->rule.exe`, while the fsnotify mark can be freed on an independent lifetime path. This creates a use-after-free window during rule deletion. Fix this by unlinking the rule from the RCU-visible lists and invoking `synchronize_rcu()` before calling `audit_remove_mark_rule()` (and other rule removal helpers). This ensures that all existing RCU readers have exited the critical section before any underlying resources are destroyed.
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
kernel/auditfilter.c
- What this is
- AUDIT SUBSYSTEMMAINTAINERS section matched on kernel/audit* · audit@vger.kernel.org · Supported
Check it on the machine
grep -w CONFIG_AUDIT /boot/config-$(uname -r)Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.
Show whether Debian builds this, per release
Debian builds this code. Every release below compiles the affected file into the kernels it ships.
- bookworm, trixie, forky, sid, bookworm · linux-6.12y
- y
- built into the kernel image on every flavour - only a patch removes it
- Build switch
- CONFIG_AUDIT
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages
Signals
- Published
- 2026-08-15 (2 months ago)source
- CVSS
- 7.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.13%, higher than 2.0% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- kernel
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 4.3 | 5.10.265 | 93616c567469 |
| 4.3 | 5.15.216 | 3f82927b399d |
| 4.3 | 6.1.183 | 8ae135a8962b |
| 4.3 | 6.6.151 | 45bf3df5b32e |
| 4.3 | 6.12.103 | 78bde7e9bd36 |
| 4.3 | 6.18.44 | cae0dfed5d30 |
| 4.3 | 7.1.8 | 5b8f46864f06 |
| 4.3 | 7.2 | 246df90b5f1a |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4788-1 | 2026-09-19 | bookworm 6.12.107-1~deb12u1 | tracker |
| DLA-4777-1 | 2026-09-08 | bookworm 6.1.187-1 | tracker |
| DSA-6466-1 | 2026-08-25 | trixie 6.12.105-1 | tracker |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:LAttack vector, local
- Reachable only via local NETLINK_AUDIT (AUDIT_DEL_RULE) or filesystem events that autoremove AUDIT_EXE rules; concurrent UAF readers run in syscall/io_uring exit audit filtering on the local host, not from remote network input.
- AC:LAttack complexity, low
- The attacker controls both sides of the race by deleting an AUDIT_EXE rule (auditctl or deleting/moving the audited executable) while driving concurrent syscall/io_uring activity to keep RCU readers in audit_filter()/audit_filter_rules().
- PR:LPrivileges required, low
- Besides CAP_AUDIT_CONTROL netlink deletion, unprivileged local users can trigger audit_del_rule() via fsnotify autoremove when deleting/moving an admin-configured audited executable they can write, without init-namespace root.
- UI:NUser interaction, none
- Exploitation requires no victim interaction; the attacker schedules rule deletion and concurrent audited syscalls/io_uring exits to hit the UAF window.
- S:UScope, unchanged
- Impact is kernel heap memory corruption and local privilege escalation within the host kernel security domain, not a documented cross-VM or IOMMU boundary escape.
- C:HConfidentiality impact, high
- Use-after-free of audit_fsnotify_mark while audit_exe_compare()/audit_mark_compare() dereference mark->ino/dev enables arbitrary kernel memory reads and info disclosure primitives.
- I:HIntegrity impact, high
- Freed fsnotify mark objects can be reallocated and corrupted to obtain arbitrary kernel writes, control-flow hijack, and local root code execution beyond audit rule deletion.
- A:HAvailability impact, high
- Concurrent dereference of a freed audit_fsnotify_mark during audit filtering can immediately oops/panic the kernel; repeated triggering yields reliable denial of service.