How severe is CVE-2026-50149?

CVE-2026-50149 has a CVSS score of 6.5/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2026-50149?

CVE-2026-50149 affects the following packages: github.com/projectcontour/contour (Go). Ecosystems affected: Go.

How do I fix CVE-2026-50149?

Update github.com/projectcontour/contour to 1.33.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-50149 is resolved across your whole dependency graph.

How do I detect CVE-2026-50149 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/projectcontour/contour, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-50149 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2026-50149 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-50149 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-50149?

CVE-2026-50149 has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 8th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-50149?

CVE-2026-50149 is classified as CWE-295 (CWE-295). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-50149 published, and has it been updated?

CVE-2026-50149 was published on August 19, 2026 and was last updated on October 21, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹

🐹 Go

Not in CISA KEV

MEDIUM severity

CVE-2026-50149 — contour

MEDIUM

CVE-2026-50149 is a medium-severity (CVSS 6.5) CWE-295 vulnerability in github.com/projectcontour/contour. A fix is available for github.com/projectcontour/contour — see the affected versions and patch details below.

Contour has Improper JWT Verification for Non-SNI Requests on Virtual Hosts with Fallback Certificate Enabled

Also known asBIT-contour-2026-50149GHSA-g3xr-5w5j-w4q4GO-2026-5889

Published

Aug 19, 2026

Updated

Oct 21, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 23, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-50149.

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs8th percentile — riskier than 8% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2026-50149 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 394,803 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

🐹github.com/projectcontour/contour

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Impact

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.

To list all HTTPProxies with this invalid configuration, run

kubectl get httpproxies -A -o json | jq -r '
  .items[]
  | select(.spec.virtualhost | .tls.enableFallbackCertificate and .jwtProviders)
  | "Invalid HTTPProxy found: \(.metadata.namespace)/\(.metadata.name)"
'

Patches

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.

Workarounds

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.

References

Contour fallback certificate documentation: https://projectcontour.io/docs/main/config/tls-termination/#fallback-certificate
Contour JWT verification documentation: https://projectcontour.io/docs/main/config/jwt-verification/

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/projectcontour/contour`	≥ 1.23.0&&< 1.33.5	1.33.5`go get github.com/projectcontour/contour@v1.33.5`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/projectcontour/contour, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/projectcontour/contour to 1.33.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-50149 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

A flaw was found in Contour. When an HTTPProxy combines enableFallbackCertificate with jwtProviders, requests without TLS SNI bypass JWT verification and are proxied without a valid token.

Workaround published by Red Hat

Upgrade to Contour v1.33.5 or later. As a workaround, do not enable enableFallbackCertificate on HTTPProxy resources that also define jwtProviders.

Source: Red Hat security advisory for CVE-2026-50149 (CC BY 4.0)

Frequently Asked Questions

### Impact 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. To list all `HTTPProxies` with this invalid configuration, run ```bash kubectl get httpproxies -A -o json | jq -r ' .items[] | select(.spec.vi