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VulnerabilityPublished Updated

CVE-2025-39886: Linux kernel · bpf: Tell memcg to use allow_spinning=false path in bpf_timer_init()

Affects Linux kernelSource GCVE Database

0

Not known to be exploited · CVSS 5.5 Medium · fixed in 6.8.0-1050.53~22.04.1 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 12:55 UTC

CVSS 3.1 base score
5.5Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 6.8.0-1050.53~22.04.1, 6.8.0-1051.57~22.04.1, 6.8.0-1052.55~22.04.1 +26
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 23 Sep 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde@6.17.0-1017.17?arch=source&distro=questingOther threatsAffected
  • 6.17.0-1003.3 – 6.17.0-1017.17
10 affected builds
Fixed in–
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux@6.8.0-106.106?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-106.106
Fixed in
  • 6.8.0-106.106
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws@6.8.0-1050.53?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1050.53
Fixed in
  • 6.8.0-1050.53
Ubuntu 24.04 LTSlinux-aws-6.14pkg:deb/ubuntu/linux-aws-6.14@6.14.0-1018.18~24.04.1?arch=source&distro=nobleOther threatsAffected
  • 6.14.0-1007.7~24.04.1 – 6.14.0-1018.18~24.04.1
11 affected builds
Fixed in–
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure@6.8.0-1051.57?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1051.57
Fixed in
  • 6.8.0-1051.57
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11@6.11.0-1018.18~24.04.1?arch=source&distro=nobleOther threatsAffected
  • 6.11.0-1008.8~24.04.1 – 6.11.0-1018.18~24.04.1
7 affected builds
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available that changes the allocation flags in __bpf_async_init() from GFP_ATOMIC to __GFP_HIGH and modifies memcg notification behavior to prevent locking issues. Users should apply the official Linux kernel updates that include this fix. The Ubuntu advisory USN-8095-1 confirms that this and other kernel vulnerabilities have been fixed in supported releases. No additional mitigation steps are indicated beyond applying the vendor-provided patches.

Description

A vulnerability in the Linux kernel's BPF subsystem involving improper handling of memory control group (memcg) accounting during bpf_timer_init() has been resolved. The flaw could cause various locking issues, including hard lockups due to double-acquiring locks when calling bpf_map_kmalloc_node() from __bpf_async_init(). The issue arises from the use of GFP_ATOMIC instead of __GFP_HIGH in __bpf_async_init(), leading to problematic memcg memory events. This vulnerability has been addressed by changing the allocation flags and related memcg notification behavior to prevent these locking conflicts.

References

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