Vulnerability in OpenVPN (CVE-2026-11771)
Summary
Vulnerability in OpenVPN (CVE-2026-11771). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
OpenVPN version 2.1.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows attackers via an off-by-one buffer write in the NTLM proxy authentication to potentially cause a crash via a crafted NTLM response from a malicious proxy server
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
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-2026-11771 has been found in OpenVPN.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "OpenVPN CVE-2026-11771" on the vendor's site.
CVE-2026-11771 (OpenVPN) — CWE-121 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
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.
A vulnerability (CWE-121) exists in OpenVPN.
Check the vendor advisory for the affected versions of OpenVPN.
Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'OpenVPN' . 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
-
1Identify exposure identify
grep -r 'OpenVPN' . | 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
OpenVPNを grep し、稼働しているサービス・バージョンを把握する。 -
2Post-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。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Alpine Linux ALPINE-CVE-2026-11771 openvpn Fixed in: 2.7.5-r0
- Debian DEBIAN-CVE-2026-11771 openvpn Fixed in: 2.6.14-0+deb12u2
- Ubuntu UBUNTU-CVE-2026-11771 openvpn Fixed in: 2.6.19-0ubuntu0.24.04.3
References
- web nvd.nist.gov
- web community.openvpn.net
- web community.openvpn.net
- web community.openvpn.net
- web github.com