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GHSA-mhvj-jhpq-885v: blaze: Multiple HTTP/1.1 request-smuggling primitives in blaze's Java wire parser

highCVSS 7.4
Summary Five independent HTTP/1.1 conformance laxities in blaze's hand-written Java parser (http/src/main/java/org/http4s/blaze/http/parser/) cause request-boundary disagreement with a stricter intermediary. All are reachable from a default BlazeServerBuilder with no non-default configuration. Impact Actual exploitability depends on the fronting proxy — a boundary disagreement requires a *pair* of parsers that disagree. Where the proxy forwards the malformed bytes and derives a different message boundary, the consequences are the standard set: front-end ACL/auth bypass, response-queue poisoning on pooled backend connections, and cache poisoning. Risk concentrates on lenient or legacy intermediaries. Workarounds Deploy behind an RFC-strict reverse proxy (nginx, HAProxy, Envoy, ALB) that rejects or re-serializes malformed requests at the edge; this neutralizes most of these for deployments that cannot upgrade immediately.

Details

Source
GitHub Security Advisories (INTL · database · site)
Severity
high — CVSS 7.4
Published
2026-07-24
Last updated
2026-07-24
Exploitation
Not in CISA KEV at last sync

Original advisory: https://github.com/advisories/GHSA-mhvj-jhpq-885v

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