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
- 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
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