CVE-2025-39886: Linux kernel · bpf: Tell memcg to use allow_spinning=false path in bpf_timer_init()
Affects Linux kernelSource GCVE Database
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, 13:47 UTC
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 23 Sep 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde@6.17.0-1017.17?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux@6.8.0-106.106?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws@6.8.0-1050.53?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
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 threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure@6.8.0-1051.57?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
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 threats | Affected
| 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
- ubuntu.com/security/CVE-2025-39886 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-39886 (opens in a new tab)
- git.kernel.org/linus/6d78b4473cdb08b74662355a9e8510bde09c511e (opens in a new tab)
- git.kernel.org/stable/c/449682e76f32601f211816d3e2100bed87e67a4c (opens in a new tab)
- git.kernel.org/stable/c/6d78b4473cdb08b74662355a9e8510bde09c511e (opens in a new tab)
- git.kernel.org/stable/c/ac70cd446f83ccb25532b343919ab86eacdcd06a (opens in a new tab)
- git.kernel.org/stable/c/cd1fd26bb13473c1734e3026b2b97025a0a4087b (opens in a new tab)
- ubuntu.com/security/notices/USN-8095-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8100-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8095-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8095-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8095-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8125-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8126-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8095-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-8165-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8261-1 (opens in a new tab)