Vulnerability details

CVE-2026-42272

dadrus heimdall

Heimdall: Case-sensitive handling of URL-encoded slashes may lead to inconsistent path interpretation

CVSS 4.0

7.8High

Official 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.

CVSS scores

Score	Version	Source	Vector
7.8High	4.0	CVEProject cvelistV5 (CNA) (GitHub_M)	`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`

Affected products

Vendor	Product	Versions	Source
dadrus	heimdall	< 0.17.14	CVEProject cvelistV5 (CNA)

References and advisories

https://github.com/dadrus/heimdall/security/advisories/GHSA-43jv-5j4x-qv67 x_refsource_CONFIRM
https://github.com/dadrus/heimdall/pull/3207 x_refsource_MISC
https://github.com/dadrus/heimdall/commit/8b0de6aba23a047cfee3081df878271bb17f4351 x_refsource_MISC
https://github.com/dadrus/heimdall/releases/tag/v0.17.14 x_refsource_MISC

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Details

Published: 2026-05-08
Last updated: 2026-05-09
State: Published
Assigner (CNA): GitHub_M

Exploit prediction (EPSS)

0.39%

Probability of exploitation in 30 days

33.9%

Percentile (among all CVEs)

SSVC assessment (CISA)

Automatable: Yes
Exploitation: None
Technical impact: Total

Weaknesses (CWE)

CWE-436
Interpretation Conflict
CWE-178
Improper Handling of Case Sensitivity