Vulnerability in gnutls (ALPINE-CVE-2026-42012)

Summary

Vulnerability in gnutls (ALPINE-CVE-2026-42012). Data can be tampered with by attackers. Mitigation: upgrade to 3.8.13-r0 or later.

Original description

The description as published by the source.

A flaw was found in gnutls. A remote attacker could exploit this vulnerability by presenting a specially crafted certificate that contains Uniform Resource Identifier (URI) or Service (SRV) Subject Alternative Names (SANs). This could cause the certificate validation process to incorrectly fall back to checking DNS hostnames against the Common Name (CN), potentially allowing the attacker to spoof legitimate services or intercept sensitive information.

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 ALPINE-CVE-2026-42012 has been found in gnutls.
Data can be tampered with by attackers.
What to do: upgrade gnutls to 3.8.13-r0 or later.
If unsure, ask your IT team or search "gnutls ALPINE-CVE-2026-42012" on the vendor's site.

ALPINE-CVE-2026-42012 (gnutls)
Attack vector: remote (network-reachable) / unauthenticated
Patched: 3.8.13-r0 — 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 gnutls.

📍 Affected scope

Check the vendor advisory for the affected versions of gnutls.

🔥 Severity

Severity: ?. Data can be tampered with by attackers.

🔧 How to fix

Update to 3.8.13-r0.

🛡️ 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 'gnutls' . 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 'gnutls' . | 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 gnutls 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 gnutls to 3.8.13-r0
```
ステージング環境で 3.8.13-r0 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。