CVE-2026-58055
MEDIUM
MEDIUM
Priority: 0.02
BB Relevance:
73/100
Published: 2026-06-28
Modified: 2026-10-25
First seen: 2026-10-29
Status: active
Attack Surface
Network
Low Complexity
No Auth
No Interaction
CVSS Vector Breakdown
AV:
Network
AC:
High
PR:
None
UI:
None
S:
X
AT:
None
VC:
Low
VI:
Low
VA:
None
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.
Weakness Classification (1)
References & Advisories (3)
Patch
Third Party Advisory
Patch
Broken Link