Vulnerability in Kernel (CVE-2025-39886)

Summary

Vulnerability in Kernel (CVE-2025-39886). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 6.6.107, 6.12.48, 6.16.8 or later.

Original description

The description as published by the source.

In the Linux kernel, the following vulnerability has been resolved:

bpf: Tell memcg to use allow_spinning=false path in bpf_timer_init()

Currently, calling bpf_map_kmalloc_node() from __bpf_async_init() can
cause various locking issues; see the following stack trace (edited for
style) as one example:

...
[10.011566] do_raw_spin_lock.cold
[10.011570] try_to_wake_up (5) double-acquiring the same
[10.011575] kick_pool rq_lock, causing a hardlockup
[10.011579] __queue_work
[10.011582] queue_work_on
[10.011585] kernfs_notify
[10.011589] cgroup_file_notify
[10.011593] try_charge_memcg (4) memcg accounting raises an
[10.011597] obj_cgroup_charge_pages MEMCG_MAX event
[10.011599] obj_cgroup_charge_account
[10.011600] __memcg_slab_post_alloc_hook
[10.011603] __kmalloc_node_noprof
...
[10.011611] bpf_map_kmalloc_node
[10.011612] __bpf_async_init
[10.011615] bpf_timer_init (3) BPF calls bpf_timer_init()
[10.011617] bpf_prog_xxxxxxxxxxxxxxxx_fcg_runnable
[10.011619] bpf__sched_ext_ops_runnable
[10.011620] enqueue_task_scx (2) BPF runs with rq_lock held
[10.011622] enqueue_task
[10.011626] ttwu_do_activate
[10.011629] sched_ttwu_pending (1) grabs rq_lock
...

The above was reproduced on bpf-next (b338cf849ec8) by modifying
./tools/sched_ext/scx_flatcg.bpf.c to call bpf_timer_init() during
ops.runnable(), and hacking the memcg accounting code a bit to make
a bpf_time…

Source: OSV.dev (Open Source Vulnerabilities) NVD OSV

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2025-39886 has been found in Kernel.
Risk of unauthorized operations or information disclosure.
What to do: upgrade Kernel to 6.6.107, 6.12.48, 6.16.8 or later.
If unsure, ask your IT team or search "Kernel CVE-2025-39886" on the vendor's site.

CVE-2025-39886 (Kernel)
Attack vector: local / no user interaction
Patched: 6.6.107, 6.12.48, 6.16.8 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (unclassified) exists in Kernel.

📍 Affected scope

Check the vendor advisory for the affected versions of Kernel.

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 6.6.107, 6.12.48, 6.16.8.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'Kernel' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

1
Identify exposure identify
```
grep -r 'Kernel' . | grep -v node_modules
```
リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で Kernel を grep し、稼働しているサービス・バージョンを把握する。
2
Apply patch patch
```
Upgrade Kernel to 6.6.107, 6.12.48, 6.16.8
```
ステージング環境で 6.6.107, 6.12.48, 6.16.8 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
3
Post-deployment verification verify
```
Confirm patched version is live in production
```
パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

Linux Kernel

[{"type":"ECOSYSTEM","events":[{"introduced":"5.15.0"},{"fixed":"6.6.107"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.48"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.16.8"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2025-39886 linux-lts
Debian DEBIAN-CVE-2025-39886 linux
Ubuntu UBUNTU-CVE-2025-39886 linux-hwe-edge