Heimdall: Forwarded Header Injection via Unsanitized Host Header in Proxy Mode
Exact source revision recorded 23 Oct 2026 16:01:20 UTC. It does not establish the source's current position. Latest evidence.
cve-program · CVE-2026-57209
PublishedHeimdall 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.
- Source published
- 23 Oct 2026 12:27:19 UTC
- Source modified
- 23 Oct 2026 12:27:19 UTC
- Observed here
- 23 Oct 2026 16:01:20 UTC
- Source terms
- CVE Program Terms of Use
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CVSS 4.0 · 7.0 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