CVE-2026-45884

Service interruption via per-CPU counter underflow

Published May 27, 2026 · Updated May 27, 2026

Integer underflow in affected Linux Kernel releases allows local users to exhaust kernel memory through high-frequency execve calls. In AppArmor's aa_get_buffer, an unconditional decrement wraps a zero per-CPU hold counter to UINT_MAX, blocking aa_put_buffer from replenishing the global buffer list. AppArmor must be enabled and the workload must repeatedly invoke execve; sustained triggering starves other CPUs and grows the kmalloc-8k slab until service degrades or fails.

CVSS severity2.0
Low
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Integer underflow in affected Linux Kernel releases allows local users to exhaust kernel memory through high-frequency execve calls. In AppArmor's aa_get_buffer, an unconditional decrement wraps a zero per-CPU hold counter to UINT_MAX, blocking aa_put_buffer from replenishing the global buffer list. AppArmor must be enabled and the workload must repeatedly invoke execve; sustained triggering starves other CPUs and grows the kmalloc-8k slab until service degrades or fails.

The record

CVE
CVE-2026-45884
Published
May 27, 2026
Updated
May 27, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 27, 2026CVE publishedPublication date reported by the CVE source.
  2. May 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=6.7
  2. Affected versionversion=ea9bae12d02819556db63348db8bd8441eb316f2 <202824a1f89a9786c20a3d646a7c88d223abb1b2
  3. Affected versionversion=ea9bae12d02819556db63348db8bd8441eb316f2 <4bcddd0f6b2e52b4c7b520e4d36a115caf5b7169
  4. Affected versionversion=ea9bae12d02819556db63348db8bd8441eb316f2 <640cf2f09575c9dc344b3f7be2498d31e3923ead
  5. Affected versionversion=ea9bae12d02819556db63348db8bd8441eb316f2 <80c334acc6d0bee8605a358a33e69b4aea1ffb92

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.7; version=ea9bae12d02819556db63348db8bd8441eb316f2 <202824a1f89a9786c20a3d646a7c88d223abb1b2; version=ea9bae12d02819556db63348db8bd8441eb316f2 <4bcddd0f6b2e52b4c7b520e4d36a115caf5b7169; version=ea9bae12d02819556db63348db8bd8441eb316f2 <640cf2f09575c9dc344b3f7be2498d31e3923ead; version=ea9bae12d02819556db63348db8bd8441eb316f2 <80c334acc6d0bee8605a358a33e69b4aea1ffb92

Published CVSS scores

5.5UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
2.0UbuntuCVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo