GHSA-G3XR-5W5J-W4Q4
Vulnerability from github – Published: 2026-07-02 17:15 – Updated: 2026-07-02 17:15Impact
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": [
{
"package": {
"ecosystem": "Go",
"name": "github.com/projectcontour/contour"
},
"ranges": [
{
"events": [
{
"introduced": "1.23.0"
},
{
"fixed": "1.33.5"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-50149"
],
"database_specific": {
"cwe_ids": [
"CWE-295"
],
"github_reviewed": true,
"github_reviewed_at": "2026-07-02T17:15:20Z",
"nvd_published_at": null,
"severity": "MODERATE"
},
"details": "### Impact\n\nWhen 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.\n\nTo list all `HTTPProxies` with this invalid configuration, run\n\n```bash\nkubectl get httpproxies -A -o json | jq -r \u0027\n .items[]\n | select(.spec.virtualhost | .tls.enableFallbackCertificate and .jwtProviders)\n | \"Invalid HTTPProxy found: \\(.metadata.namespace)/\\(.metadata.name)\"\n\u0027\n```\n\n### Patches\n\nThis 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`.\n\n### Workarounds\n\nDo 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.\n\n### References\n\n- Contour fallback certificate documentation: https://projectcontour.io/docs/main/config/tls-termination/#fallback-certificate\n- Contour JWT verification documentation: https://projectcontour.io/docs/main/config/jwt-verification/",
"id": "GHSA-g3xr-5w5j-w4q4",
"modified": "2026-07-02T17:15:20Z",
"published": "2026-07-02T17:15:20Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/projectcontour/contour/security/advisories/GHSA-g3xr-5w5j-w4q4"
},
{
"type": "PACKAGE",
"url": "https://github.com/projectcontour/contour"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N",
"type": "CVSS_V3"
}
],
"summary": "Contour has Improper JWT Verification for Non-SNI Requests on Virtual Hosts with Fallback Certificate Enabled"
}
Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline
Sightings and recorded dates, grouped by day · UTC
Loading timeline…
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.