Answer in brief
CVE-2026-57209 records a High severity (CVSS 7.0) vulnerability in Heimdall: Forwarded Header Injection via Unsanitized Host Header in Proxy Mode. The current sources do not mark it as known exploited. The current feed maps dadrus/heimdall (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.0. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps dadrus/heimdall (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| dadrus/heimdallgeneric | <0.17.17 | 0.17.17 |
Published upstream
Oct 23, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 23, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 23, 2026
Heimdall is a cloud native Identity Aware Proxy and Access Control Decision service. Prior to version 0.17.17, when Heimdall operates in proxy mode, it constructs the Forwarded HTTP header after executing the matched rule pipeline by inserting the incoming request's Host header value directly into the header string without sanitizing commas or semicolons. This allows an attacker to inject additional parameters into the Forwarded header, potentially spoofing IP addresses for upstream services. This issue has been patched in version 0.17.17.
Quoted source text, attributed separately from HOL analysis.