CVE-2026-42272
HIGHHeimdall: Case-sensitive handling of URL-encoded slashes may lead to inconsistent path interpretation
Title source: cnaDescription
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.
References (4)
Core 4
Core References
X_Refsource_Confirm x_refsource_confirm
https://github.com/dadrus/heimdall/security/advisories/GHSA-43jv-5j4x-qv67
X_Refsource_Misc x_refsource_misc
https://github.com/dadrus/heimdall/pull/3207
X_Refsource_Misc x_refsource_misc
https://github.com/dadrus/heimdall/commit/8b0de6aba23a047cfee3081df878271bb17f4351
X_Refsource_Misc x_refsource_misc
https://github.com/dadrus/heimdall/releases/tag/v0.17.14
Scores
CVSS v4
7.8
EPSS
0.0002
EPSS Percentile
5.0%
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
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
yes
Technical Impact
total
Details
CWE
CWE-178
CWE-436
Status
published
Products (2)
dadrus/heimdall
0 - 0.17.14Go
dadrus/heimdall
< 0.17.14
Published
May 08, 2026
Tracked Since
May 08, 2026