What’s Vulnerable › Vulnerabilities

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

• Severity: high (CVSS 7.8 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-05-08 · updated 2026-10-26
• Weakness: CWE-35

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 products

• dadrus heimdall: before 0.17.14

References

• https://github.com/dadrus/heimdall/commit/b5dfa484b7a8c2ce6d8691c026f9da867719947a
• https://github.com/dadrus/heimdall/pull/3209
• https://github.com/dadrus/heimdall/releases/tag/v0.17.14
• https://github.com/dadrus/heimdall/security/advisories/GHSA-3q34-rx83-r6mq

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