Heimdall is a cloud native Identity Aware Proxy and Access Control Decision service. Prior to version 0.17.14, Heimdall handles URL-encoded slashes (%2F) in a case-sensitive manner, while percent-encoding is defined to be case-insensitive. As a result, the lowercase equivalent (%2f) is not recognized and therefore not processed as expected when allow_encoded_slashes is set to off (the default setting). This discrepancy can lead to differences in how request paths are interpreted by heimdall and upstream components, which may result in authorization bypass. This issue has been patched in version 0.17.14.

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-43jv-5j4x-qv67 Heimdall: Case-sensitive handling of URL-encoded slashes may lead to inconsistent path interpretation
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Fri, 08 May 2026 05:45:00 +0000

Type Values Removed Values Added
First Time appeared Dadrus
Dadrus heimdall
Vendors & Products Dadrus
Dadrus heimdall

Fri, 08 May 2026 04:00:00 +0000

Type Values Removed Values Added
Description Heimdall is a cloud native Identity Aware Proxy and Access Control Decision service. Prior to version 0.17.14, Heimdall handles URL-encoded slashes (%2F) in a case-sensitive manner, while percent-encoding is defined to be case-insensitive. As a result, the lowercase equivalent (%2f) is not recognized and therefore not processed as expected when allow_encoded_slashes is set to off (the default setting). This discrepancy can lead to differences in how request paths are interpreted by heimdall and upstream components, which may result in authorization bypass. This issue has been patched in version 0.17.14.
Title Heimdall: Case-sensitive handling of URL-encoded slashes may lead to inconsistent path interpretation
Weaknesses CWE-178
CWE-436
References
Metrics cvssV4_0

{'score': 7.8, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-05-08T03:40:17.541Z

Reserved: 2026-04-26T11:53:27.707Z

Link: CVE-2026-42272

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-05-08T04:16:22.013

Modified: 2026-05-08T04:16:22.013

Link: CVE-2026-42272

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-08T05:30:46Z

Weaknesses