Vulnerability in Kernel (CVE-2025-38544)

Summary

Vulnerability in Kernel (CVE-2025-38544). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 6.6.99, 6.12.39, 6.15.7 or later.

Original description

The description as published by the source.

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

rxrpc: Fix bug due to prealloc collision

When userspace is using AF_RXRPC to provide a server, it has to preallocate
incoming calls and assign to them call IDs that will be used to thread
related recvmsg() and sendmsg() together. The preallocated call IDs will
automatically be attached to calls as they come in until the pool is empty.

To the kernel, the call IDs are just arbitrary numbers, but userspace can
use the call ID to hold a pointer to prepared structs. In any case, the
user isn't permitted to create two calls with the same call ID (call IDs
become available again when the call ends) and EBADSLT should result from
sendmsg() if an attempt is made to preallocate a call with an in-use call
ID.

However, the cleanup in the error handling will trigger both assertions in
rxrpc_cleanup_call() because the call isn't marked complete and isn't
marked as having been released.

Fix this by setting the call state in rxrpc_service_prealloc_one() and then
marking it as being released before calling the cleanup function.

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-2025-38544 has been found in Kernel.
Risk of unauthorized operations or information disclosure.
What to do: upgrade Kernel to 6.6.99, 6.12.39, 6.15.7 or later.
If unsure, ask your IT team or search "Kernel CVE-2025-38544" on the vendor's site.

CVE-2025-38544 (Kernel)
Patched: 6.6.99, 6.12.39, 6.15.7 — 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 6.6.99, 6.12.39, 6.15.7.

🛡️ 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 6.6.99, 6.12.39, 6.15.7
```
ステージング環境で 6.6.99, 6.12.39, 6.15.7 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":"4.9.0"},{"fixed":"6.6.99"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.39"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.15.7"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2025-38544 linux-lts
Debian DEBIAN-CVE-2025-38544 linux
Ubuntu UBUNTU-CVE-2025-38544 linux-azure