CVE-2026-42274 HIGH

CVE-2026-42274: Heimdall: Authorization bypass via path normalization mismatch

Vendor Dadrus
Product heimdall
Weakness CWE-35
Published May 8, 2026
Last update May 11, 2026

CVSS base score

7.8/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality
Integrity

CVSS 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

What the vulnerability does

01Description

Heimdall is a cloud native Identity Aware Proxy and Access Control Decision service. Prior to version 0.17.14, Heimdall performs rule matching on the raw (non-normalized) request path, while downstream components may normalize dot-segments according to RFC 3986, Section 6.2.2.3. This discrepancy can result in heimdall authorizing a request for one path (e.g., /user/../admin, or URL-encoded variants such as /user/%2e%2e/admin or /user/%2e%2e%2fadmin. The latter would require the allow_encoded_slashes option to be set to on or no_decode.) while the downstream ultimately processes a different, normalized path (/admin). This issue has been patched in version 0.17.14.

Key dates

02Disclosure timeline

May 8, 2026 CVE published
May 11, 2026 Record updated