CVE-2026-45884

apparmor: avoid per-cpu hold underflow in aa_get_buffer

MEDIUM
5.5
CVSS Score
Published: May 27, 2026 at 12:16 PM UTC
Updated: June 27, 2026 at 11:41 AM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
MEDIUM5.5
Exploit prediction
EPSS 0.2%

Description

In the Linux kernel, the following vulnerability has been resolved: apparmor: avoid per-cpu hold underflow in aa_get_buffer When aa_get_buffer() pulls from the per-cpu list it unconditionally decrements cache->hold. If hold reaches 0 while count is still non-zero, the unsigned decrement wraps to UINT_MAX. This keeps hold non-zero for a very long time, so aa_put_buffer() never returns buffers to the global list, which can starve other CPUs and force repeated kmalloc(aa_g_path_max) allocations. Guard the decrement so hold never underflows.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

6.13 ≤ v < 6.18.146.19 ≤ v < 6.19.46.7 ≤ v < 6.12.756.7 ≤ v < 6.18.146.7 ≤ v < 6.19.46.7 ≤ v < 7.06.7ea9bae12d02819556db63348db8bd8441eb316f2
Vendor states this is fixed in 202824a1f89a9786c20a3d646a7c88d223abb1b2 (fixed)
Vendor states this is fixed in 4bcddd0f6b2e52b4c7b520e4d36a115caf5b7169 (fixed)
Vendor states this is fixed in 640cf2f09575c9dc344b3f7be2498d31e3923ead (fixed)
Vendor states this is fixed in 80c334acc6d0bee8605a358a33e69b4aea1ffb92 (fixed)
Vendor states this is fixed in 6.12.75 (unaffected)
Vendor states this is fixed in 6.18.14 (unaffected)
Vendor states this is fixed in 6.19.4 (unaffected)
Vendor states this is fixed in 6.7 (unaffected)
Vendor states this is fixed in 7.0 (unaffected)

CVSS

Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-191

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