IP Address Validation Flaw in Heimdall Identity Aware Proxy by Dadrus
CVE-2026-57210

7HIGH

Key Information:

Vendor

Dadrus

Status
Heimdall
Vendor
CVE Published:
23 October 2026

What is CVE-2026-57210?

Heimdall, a cloud-native Identity Aware Proxy and Access Control Decision service, has a vulnerability that allows arbitrary and malformed IP address values to bypass validation checks. This occurs due to how the system extracts client IP addresses from the Forwarded and X-Forwarded-For headers when the trusted_proxies option is configured. The lack of proper syntax validation for these extracted values can lead to security issues, as it allows malformed IP literals and other unforeseen inputs. Furthermore, the parser's handling of Forwarded headers does not account for RFC 7239 quoted strings, potentially leading to incorrect parsing of intended single quoted IP addresses as multiple entries. This flaw has been addressed in Heimdall version 0.17.17.

Affected Version(s)

heimdall < 0.17.17

References

https://github.com/dadrus/heimdall/security/advisories/GH...
x_refsource_CONFIRM
https://github.com/dadrus/heimdall/releases/tag/v0.17.17
x_refsource_MISC

CVSS V4

Score:
7
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
Physical
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.