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CVE PROGRAM SOURCE RECORD6.3 Medium

CVE-2026-58055

nghttp2 nghttpx - HTTP Request/Response Smuggling via Upgrade Request with Content-Length

Description

nghttp2's nghttpx proxy through 1.69.0 forwards an HTTP/1.1 Upgrade request that also carries a Content-Length header and body onto reusable keep-alive backend connections, re-adding the Upgrade and Connection headers while passing Content-Length verbatim. A backend that resolves the resulting ambiguous message in the attacker's favor enables HTTP request/response smuggling and cross-client response-queue poisoning.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

nghttp2 nghttp2

Default version status: affected

  • 0 to ≤ 1.69.0affected

References