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CVE-2026-72459
apparmor: aa_label_alloc use aa_label_free on alloc failure
Published 2026-08-15 (2 months ago) by the Linux kernel CNA. Subsystem security/apparmor. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-72459 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 | fixed | 6.1.180-1 | Update the kernel and reboot. Fixed in 6.1.180-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.100-1 | Update the kernel and reboot. Fixed in 6.12.100-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
aa_label_alloc() allocates a secid before allocating or taking the label proxy. If the later proxy step fails, the error path only freed the label memory, leaking any resources initialized by aa_label_init(). Use aa_label_free() on the failure path so partially initialized labels release their secid and other label resources before the backing memory is freed.
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.
security/apparmor/label.c
- What this is
- APPARMOR SECURITY MODULEMAINTAINERS section matched on security/apparmor/ · apparmor@lists.ubuntu.com · Supported
Check it on the machine
grep -w CONFIG_SECURITY_APPARMOR /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, sidy
- y
- built into the kernel image on every flavour - only a patch removes it
- Build switch
- CONFIG_SECURITY_APPARMOR
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
- 0.14%, higher than 2.9% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- security/apparmor
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 4.13 | 5.10.261 | b14fbacad77d |
| 4.13 | 5.15.212 | b5a9da5d3616 |
| 4.13 | 6.1.178 | 7cb69e109610 |
| 4.13 | 6.6.145 | cc2192899d50 |
| 4.13 | 6.12.97 | bf310b044e85 |
| 4.13 | 6.18.40 | ae02e603c0b3 |
| 4.13 | 7.1.5 | 6d9147917424 |
| 4.13 | 7.2 | 654fe7505dc6 |
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
- The bug is in AppArmor LSM label allocation reached only through local kernel entry points (open/read/exec, unix socket mediation, change_hat/change_profile procattr) on AppArmor-enabled systems, not via remote network packet handling.
- AC:LAttack complexity, low
- Triggering proxy allocation failure after secid allocation requires memory pressure, but an attacker can reliably induce kmalloc/GFP_ATOMIC exhaustion locally (memfd, large mappings, stress) while driving aa_label_merge through routine file or socket operations.
- PR:LPrivileges required, low
- Any unprivileged local process running under AppArmor (default on Ubuntu, Debian, SUSE, Android) can reach aa_label_merge/aa_label_alloc through normal permitted file access, exec domain transitions, or unix-socket mediation without real-root or CAP_MAC_ADMIN.
- UI:NUser interaction, none
- Exploitation requires no victim or administrator interaction; the attacker uses only their own credentials and syscalls to create memory pressure and invoke AppArmor label-merge paths.
- S:UScope, unchanged
- Impact is kernel memory corruption, information disclosure, and denial of service within the host kernel security domain; it does not cross a VM, container, or IOMMU security boundary by itself.
- C:HConfidentiality impact, high
- The error path called kfree() without aa_free_secid(), leaving the global secid xarray pointing at freed aa_label memory; aa_secid_to_label()/apparmor_secid_to_secctx() then dereference attacker-influenced freed slab for arbitrary kernel memory reads.
- I:HIntegrity impact, high
- Orphaned secid entries retain dangling aa_label pointers whose vec/profile fields can be reclaimed and sprayed; UAF traversal of those structures is a standard path to heap control and arbitrary kernel writes or code execution.
- A:HAvailability impact, high
- Dereferencing stale label/profile pointers can cause kernel oops/panic, and each successful trigger permanently leaks a secid slot until reboot, eventually exhausting the global secid table and denying all future AppArmor label creation system-wide.