CVE-2026-42274: Heimdall has an authorization bypass via path normalization mismatch
(updated )
Heimdall performs rule matching on the raw (non-normalized) request path, while downstream components may normalize dot-segments according to RFC 3986, Section 6.2.2.3. This discrepancy can result in heimdall authorizing a request for one path (e.g., /user/../admin, or URL-encoded variants such as /user/%2e%2e/admin or /user/%2e%2e%2fadmin. The latter would require the allow_encoded_slashes option to be set to on or no_decode.) while the downstream ultimately processes a different, normalized path (/admin).
References
- github.com/advisories/GHSA-3q34-rx83-r6mq
- github.com/dadrus/heimdall/commit/b5dfa484b7a8c2ce6d8691c026f9da867719947a
- github.com/dadrus/heimdall/pull/3209
- github.com/dadrus/heimdall/releases/tag/v0.17.14
- github.com/dadrus/heimdall/security/advisories/GHSA-3q34-rx83-r6mq
- nvd.nist.gov/vuln/detail/CVE-2026-42274
- www.envoyproxy.io/docs/envoy/latest/api-v3/extensions/filters/network/http_connection_manager/v3/http_connection_manager.proto
- www.rfc-editor.org/rfc/rfc3986
Code Behaviors & Features
Detect and mitigate CVE-2026-42274 with GitLab Dependency Scanning
Secure your software supply chain by verifying that all open source dependencies used in your projects contain no disclosed vulnerabilities. Dependency Scanning using SBOM also detects vulnerabilities from proprietary advisories that this site does not include. Learn more about Dependency Scanning using SBOM →