Heimdall is a cloud native Identity Aware Proxy and Access Control Decision service. Prior to version 0.17.17, when the trusted_proxies option is configured, heimdall extracts client IP addresses from the Forwarded (for= parameter) and X-Forwarded-For headers and exposes them as Request.ClientIPAddresses to the rule pipeline. However, extracted values are not validated to be syntactically valid IP addresses. Arbitrary strings, malformed IP literals, and RFC 7239 unknown values and obfuscated identifiers are accepted without further checks. In addition, the Forwarded header parser splits on , and ; without accounting for RFC 7239 quoted strings, which can cause a single quoted value to be parsed as multiple entries, with fragments — including trailing quote characters — treated as independent addresses. This issue has been patched in version 0.17.17.
History

Thu, 29 Oct 2026 03:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 23 Oct 2026 14:00:00 +0000

Type Values Removed Values Added
First Time appeared Dadrus
Dadrus heimdall
Vendors & Products Dadrus
Dadrus heimdall

Fri, 23 Oct 2026 12:45:00 +0000

Type Values Removed Values Added
Description Heimdall is a cloud native Identity Aware Proxy and Access Control Decision service. Prior to version 0.17.17, when the trusted_proxies option is configured, heimdall extracts client IP addresses from the Forwarded (for= parameter) and X-Forwarded-For headers and exposes them as Request.ClientIPAddresses to the rule pipeline. However, extracted values are not validated to be syntactically valid IP addresses. Arbitrary strings, malformed IP literals, and RFC 7239 unknown values and obfuscated identifiers are accepted without further checks. In addition, the Forwarded header parser splits on , and ; without accounting for RFC 7239 quoted strings, which can cause a single quoted value to be parsed as multiple entries, with fragments — including trailing quote characters — treated as independent addresses. This issue has been patched in version 0.17.17.
Title Heimdall: IP Spoofing via Unvalidated Forwarding Headers
Weaknesses CWE-116
CWE-20
CWE-290
References
Metrics cvssV4_0

{'score': 7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-10-23T12:28:09.427Z

Updated: 2026-10-29T02:57:12.693Z

Reserved: 2026-06-24T02:00:46.801Z

Link: CVE-2026-57210

cve-icon Vulnrichment

Updated: 2026-10-29T02:57:08.581Z

cve-icon NVD

Status : Deferred

Published: 2026-10-23T13:17:11.847

Modified: 2026-10-23T19:57:42.660

Link: CVE-2026-57210

cve-icon Redhat

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