Unauthenticated host validation bypass via forwarded-host fallback
Published Aug 3, 2026 · Updated Aug 3, 2026
Host validation bypass in Litestar before 2.22.0 allows remote attackers to submit requests under an allowed host without authentication. AllowedHostsMiddleware.call falls back from a missing Host header to the client-controlled X-Forwarded-Host value and validates it against the allowlist. Exposure requires AllowedHostsConfig plus HTTP/1.0 acceptance or a deployment that does not strip X-Forwarded-Host, enabling reset-link, cache, or routing manipulation.
Summary
What happened
Host validation bypass in Litestar before 2.22.0 allows remote attackers to submit requests under an allowed host without authentication. AllowedHostsMiddleware.call falls back from a missing Host header to the client-controlled X-Forwarded-Host value and validates it against the allowlist. Exposure requires AllowedHostsConfig plus HTTP/1.0 acceptance or a deployment that does not strip X-Forwarded-Host, enabling reset-link, cache, or routing manipulation.
The record
- CVE
- CVE-2026-48061
- Published
- Aug 3, 2026
- Updated
- Aug 3, 2026
- Vendor
- Litestar
- Product
- Litestar
- Classifications
- CWE-644, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 3, 2026CVE publishedPublication date reported by the CVE source.
- Aug 3, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 2.22.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Allowed Hosts Bypass via X-Forwarded-Host PoCproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo