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Vulnerability · Published May 8, 2026 · Assigned by GitHub_M

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

High 7.8

In plain English

A high-severity security flaw in heimdall from dadrus. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 31% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)7.8High
Exploit odds (30 days)0.4%top 69.2% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Gogithub.com/dadrus/heimdall0.17.14GHSA-3q34-rx83-r6mq
Gogithub.com/dadrus/heimdall0.17.14GO-2026-5097

Affected products (as reported)

VendorProductVersions
dadrus heimdall < 0.17.14

Weakness: CWE-35, CWE-436 · 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

References