Vulnerability in github.com/projectcontour/contour (CVE-2026-50149)
Summary
Vulnerability in github.com/projectcontour/contour (CVE-2026-50149). Confidential information can be exposed externally. Exploitable via HTTPProxy. Mitigation: upgrade to 1.33.5 or later.
Original description
The description as published by the source.
Contour is a Kubernetes ingress controller using Envoy proxy. In versions 1.23.0 through 1.33.4, when an HTTPProxy is configured with incompatible combination of both .spec.virtualhost.tls.enableFallbackCertificate: true and .spec.virtualhost.jwtProviders, Contour does not reject the configuration. Consequently, requests from clients that do not send TLS SNI or send an unrecognized SNI (one that does not match any HTTPProxy FQDN) bypass configured JWT verification and are proxied to upstream services without a valid token. This issue is fixed in Contour v1.33.5. Contour now rejects and marks invalid any HTTPProxy resources that combine .spec.virtualhost.tls.enableFallbackCertificate: true with .spec.virtualhost.jwtProviders. Affected resources will receive a status condition with the error reason TLSIncompatibleFeatures. As a workaround, do not enable .spec.virtualhost.tls.enableFallbackCertificate on HTTPProxy resources that also define .spec.virtualhost.jwtProviders. Remove one of the two settings to avoid the invalid configuration.
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-2026-50149 has been found in github.com/projectcontour/contour.
Attackers can target a specific entry point like HTTPProxy over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 6.5/10.
What to do: upgrade github.com/projectcontour/contour to 1.33.5 or later.
If unsure, ask your IT team or search "github.com/projectcontour/contour CVE-2026-50149" on the vendor's site.
CVE-2026-50149 (github.com/projectcontour/contour) — CWE-295 / CVSS v3 6.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: HTTPProxy / HTTPProxies / TLSIncompatibleFeatures
Patched: 1.33.5 — apply immediately
Workaround: Do not enable .spec.virtualhost.tls.enableFallbackCertificate on HTTPProxy resources that also define .spec.virtualhost.jwtProviders.
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-295) exists in github.com/projectcontour/contour. Attackers reach the vulnerable code path via HTTPProxy without authentication.
Check the vendor advisory for the affected versions of github.com/projectcontour/contour. Attack surface: HTTPProxy / HTTPProxies / TLSIncompatibleFeatures.
Severity: Medium (CVSS 6.5/10). Confidential information can be exposed externally.
Update to 1.33.5.
Workaround: Do not enable .spec.virtualhost.tls.enableFallbackCertificate on HTTPProxy resources that also define .spec.virtualhost.jwtProviders.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'github.com/projectcontour/contour' . 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 'github.com/projectcontour/contour' . | 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
github.com/projectcontour/contourを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply temporary workaround mitigate
Do not enable `.spec.virtualhost.tls.enableFallbackCertificate` on `HTTPProxy` resources that also define `.spec.virtualhost.jwtProviders`.パッチが適用されるまでの応急処置として、Do not enable
.spec.virtualhost.tls.enableFallbackCertificateonHTTPProxyresources that also define.spec.virtualhost.jwtProviders. を実施。回避策の副作用 (機能低下) を確認した上で。 -
3Apply patch patch
Upgrade github.com/projectcontour/contour to 1.33.5ステージング環境で 1.33.5 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。
-
4Post-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
References
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- web github.com