Vulnerability in Kernel (CVE-2025-39992)

Summary

Vulnerability in Kernel (CVE-2025-39992). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 6.12.51, 6.16.11, 6.17.1 or later.

Original description

The description as published by the source.

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

mm: swap: check for stable address space before operating on the VMA

It is possible to hit a zero entry while traversing the vmas in unuse_mm()
called from swapoff path and accessing it causes the OOPS:

Unable to handle kernel NULL pointer dereference at virtual address
0000000000000446--> Loading the memory from offset 0x40 on the
XA_ZERO_ENTRY as address.
Mem abort info:
ESR = 0x0000000096000005
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x05: level 1 translation fault

The issue is manifested from the below race between the fork() on a
process and swapoff:
fork(dup_mmap()) swapoff(unuse_mm)

Identical mtree is built using
__mt_dup().
copy_pte_range()-->
copy_nonpresent_pte():
The dst mm is added into the
mmlist to be visible to the
swapoff operation.

Fatal signal is sent to the parent
process(which is the current during the
fork) thus skip the duplication of the
vmas and mark the vma range with
XA_ZERO_ENTRY as a marker for this process
that helps during exit_mmap().

 		     4) swapoff is tried on the
 			'mm' added to the 'mmlist' as
 			part of the 2.

 		     5) unuse_mm(), that iterates
 			through the vma's of this 'mm'
 			will hit the non-NULL zero entry
 			and operating on this zero entry
 			as a vma is resulting into the
 			oops.

The proper fi…

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-2025-39992 has been found in Kernel.
Risk of unauthorized operations or information disclosure.
What to do: upgrade Kernel to 6.12.51, 6.16.11, 6.17.1 or later.
If unsure, ask your IT team or search "Kernel CVE-2025-39992" on the vendor's site.

CVE-2025-39992 (Kernel)
Patched: 6.12.51, 6.16.11, 6.17.1 — 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 6.12.51, 6.16.11, 6.17.1.

🛡️ 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 6.12.51, 6.16.11, 6.17.1
```
ステージング環境で 6.12.51, 6.16.11, 6.17.1 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":"6.8.0"},{"fixed":"6.12.51"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.16.11"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.17.0"},{"fixed":"6.17.1"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2025-39992 linux-lts Fixed in: 6.12.51-r0
Debian DEBIAN-CVE-2025-39992 linux Fixed in: 6.12.57-1
Ubuntu UBUNTU-CVE-2025-39992 linux