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EUVD-2026-28508 · Published May 8, 2026
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.
Technologies
Dadrus Heimdall
Weaknesses
CWE-178CWE-436
CVSS scores
- v4.07.8
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
MITRE ATT&CK
InferredWhere this vulnerability fits in an attack
Initial Access
References
- https://github.com/dadrus/heimdall/commit/8b0de6aba23a047cfee3081df878271bb17f4351
- https://github.com/dadrus/heimdall/pull/3207
- https://github.com/dadrus/heimdall/releases/tag/v0.17.14
- https://github.com/dadrus/heimdall/security/advisories/GHSA-43jv-5j4x-qv67
- https://nvd.nist.gov/vuln/detail/CVE-2026-42272
- https://github.com/dadrus/heimdall
Potentially impacted assets
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