Vulnerability in gnutls28 (DEBIAN-CVE-2026-42011)

Summary

Vulnerability in gnutls28 (DEBIAN-CVE-2026-42011). Confidential information can be exposed externally. Mitigation: upgrade to 3.7.1-5+deb11u10 or later.

Original description

The description as published by the source.

A flaw was found in gnutls. This vulnerability occurs because permitted name constraints were incorrectly ignored when previous Certificate Authorities (CAs) only had excluded name constraints. A remote attacker could exploit this to bypass critical name constraint checks during certificate validation. This bypass could lead to the acceptance of invalid certificates, potentially enabling spoofing or man-in-the-middle attacks against affected systems.

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 DEBIAN-CVE-2026-42011 has been found in gnutls28.
Confidential information can be exposed externally.
What to do: upgrade gnutls28 to 3.7.1-5+deb11u10 or later.
If unsure, ask your IT team or search "gnutls28 DEBIAN-CVE-2026-42011" on the vendor's site.

DEBIAN-CVE-2026-42011 (gnutls28)
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 3.7.1-5+deb11u10 — 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 gnutls28.

📍 Affected scope

Check the vendor advisory for the affected versions of gnutls28.

🔥 Severity

Severity: ?. Confidential information can be exposed externally.

🔧 How to fix

Update to 3.7.1-5+deb11u10.

🛡️ 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 'gnutls28' . 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 'gnutls28' . | 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 gnutls28 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 gnutls28 to 3.7.1-5+deb11u10
```
ステージング環境で 3.7.1-5+deb11u10 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

Debian:11 gnutls28

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.7.1-5+deb11u10"}]}]

Debian:12 gnutls28

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.7.9-2+deb12u7"}]}]

Debian:13 gnutls28

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.8.9-3+deb13u4"}]}]

Debian:14 gnutls28

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.8.13-1"}]}]

References

advisory security-tracker.debian.org