Vulnerability in cifs-utils (UBUNTU-CVE-2026-12505)

Summary

Vulnerability in cifs-utils (UBUNTU-CVE-2026-12505). Successful exploitation can lead to full system takeover. Mitigation: upgrade to 2:6.14-1ubuntu0.6 or later.

Original description

The description as published by the source.

A flaw was found in the cifs-utils package where the cifs.upcall helper fails to securely drop its root privileges before looking up user information inside a user-controlled environment. A local, low privileged attacker can exploit this by using a crafted request_key payload to trick the root-owned helper into entering a custom environment (namespace) containing a malicious NSS module. This forces the system to load the attacker's controlled NSS Module and configuration, allowing them to execute arbitrary commands as the root user, elevating their privileges and fully compromising the system.

Source: OSV.dev (Open Source Vulnerabilities) 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 UBUNTU-CVE-2026-12505 has been found in cifs-utils.
Successful exploitation can lead to full system takeover.
What to do: upgrade cifs-utils to 2:6.14-1ubuntu0.6 or later.
If unsure, ask your IT team or search "cifs-utils UBUNTU-CVE-2026-12505" on the vendor's site.

UBUNTU-CVE-2026-12505 (cifs-utils)
Attack vector: local / no user interaction
Patched: 2:6.14-1ubuntu0.6 — 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 cifs-utils.

📍 Affected scope

Check the vendor advisory for the affected versions of cifs-utils.

🔥 Severity

Severity: ?. Successful exploitation can lead to full system takeover.

🔧 How to fix

Update to 2:6.14-1ubuntu0.6.

🛡️ 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 'cifs-utils' . 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 'cifs-utils' . | 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 cifs-utils 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 cifs-utils to 2:6.14-1ubuntu0.6
```
ステージング環境で 2:6.14-1ubuntu0.6 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。