Identity Aware Proxy and Access Control Decision Service Vulnerability in Heimdall
CVE-2026-57209

7HIGH

Key Information:

Vendor

Dadrus

Status
Heimdall
Vendor
CVE Published:
23 October 2026

What is CVE-2026-57209?

Heimdall, a cloud-native Identity Aware Proxy and Access Control Decision service, is susceptible to an HTTP header injection vulnerability. When running in proxy mode prior to version 0.17.17, Heimdall improperly constructs the Forwarded HTTP header by inserting the request's Host header value without sanitizing against commas or semicolons. This flaw can allow attackers to inject unauthorized parameters into the Forwarded header, potentially leading to IP address spoofing of upstream services.

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

.