# CVE-2026-42274: dadrus Heimdall authorization bypass via path normalization mismatch

Source: https://junglewise.ai/threats/cve-2026-42274-dadrus-heimdall-authorization-bypass-via-path-normalization  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-08. Updated: 2026-05-12  
License: CC BY 4.0 with a link back

CVE-2026-42274 · Severity: high · CVSS 4 · Published 2026-05-08

Heimdall, an identity and access proxy, is vulnerable to an authorization bypass. An attacker can use specially crafted web addresses containing relative path sequences (like /../) to trick the system into applying security rules for a public area to a restricted area. This could allow unauthorized users to access sensitive data or perform administrative actions without proper authentication.

Technologies: [Dadrus Heimdall](https://junglewise.ai/threats/technologies/heimdall), [github.com/dadrus/heimdall (Go)](https://junglewise.ai/threats/technologies/github-com-dadrus-heimdall). Vendors: [Dadrus](https://junglewise.ai/threats/vendors/dadrus), [Go](https://junglewise.ai/threats/vendors/go).

## Quick answers

**Is CVE-2026-42274 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-42274 being exploited in the wild.

**How severe is CVE-2026-42274?** High severity, with a CVSS score of 4, published 8 May 2026.

**Which products and versions are affected?** Dadrus Heimdall < 0.17.14; github.com/dadrus/heimdall (Go) < 0.17.14, SEMVER:introduced=0,fixed=0.17.14.

**Is there a fix for CVE-2026-42274?** Yes. github.com/dadrus/heimdall (Go): upgrade to 0.17.14 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-42274 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-42274?** Check whether you run Dadrus Heimdall or github.com/dadrus/heimdall (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- github.com/dadrus/heimdall (Go): upgrade to 0.17.14 or later

  ```sh
  go get github.com/dadrus/heimdall@v0.17.14
  ```


## Technical details

Heimdall performs rule matching on raw, non-normalized request paths, while downstream components may normalize dot-segments (RFC 3986). An attacker can exploit this by using path traversal sequences (e.g., /public/../admin) to match a permissive rule in Heimdall while the downstream service resolves the path to a restricted resource. This is particularly effective when Heimdall is configured with wildcard routes. The vulnerability is addressed in version 0.17.14. Workarounds include enforcing path normalization at the ingress/proxy layer (e.g., using Envoy's normalize_path) or validating rule IDs within issued JWTs.

## Affected products

- dadrus Heimdall < 0.17.14

## Identifiers

- CVE-2026-42274
- GHSA-3q34-rx83-r6mq
- GO-2026-5097

## Timeline

- 2026-04-21: disclosed: Advisory published by dadrus
- 2026-04-25: advisory: GitHub Advisory published
- 2026-04-25: patched: Fix released in version 0.17.14

## References

- [https://github.com/dadrus/heimdall/security/advisories/GHSA-3q34-rx83-r6mq](https://github.com/dadrus/heimdall/security/advisories/GHSA-3q34-rx83-r6mq)
- [https://www.envoyproxy.io/docs/envoy/latest/api-v3/extensions/filters/network/http_connection_manager/v3/http_connection_manager.proto](https://www.envoyproxy.io/docs/envoy/latest/api-v3/extensions/filters/network/http_connection_manager/v3/http_connection_manager.proto)
- [https://www.rfc-editor.org/rfc/rfc3986](https://www.rfc-editor.org/rfc/rfc3986)
- [https://github.com/dadrus/heimdall/pull/3209](https://github.com/dadrus/heimdall/pull/3209)
- [https://github.com/dadrus/heimdall/commit/b5dfa484b7a8c2ce6d8691c026f9da867719947a](https://github.com/dadrus/heimdall/commit/b5dfa484b7a8c2ce6d8691c026f9da867719947a)

## Related threats

- [Heimdall IP spoofing via unvalidated forwarding headers](https://junglewise.ai/threats/cve-2026-57210-heimdall-ip-spoofing-via-unvalidated-forwarding-headers)
- [Heimdall Forwarded header injection in proxy mode](https://junglewise.ai/threats/cve-2026-57209-heimdall-forwarded-header-injection-via-unsanitized-host-header)
- [Dadrus Heimdall case-sensitive host matching policy bypass](https://junglewise.ai/threats/cve-2026-42273-dadrus-heimdall-case-sensitive-host-matching-policy-bypass)
- [dadrus Heimdall authorization bypass via case-sensitive URL encoding](https://junglewise.ai/threats/cve-2026-42272-dadrus-heimdall-authorization-bypass-via-case-sensitive-url)
- [GO-2026-4742 - Heimdall: Path received via Envoy gRPC corrupted when containing query string in github.com/dadrus/heimdall](https://junglewise.ai/threats/cve-2026-32811-heimdall-path-received-via-envoy-grpc-corrupted-when-containing)