CVE-2026-58055 Details
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.
A vulnerability in nghttp2's nghttpx proxy, affecting versions through 1.69.0, allows for HTTP request/response smuggling. This occurs when an HTTP/1.1 Upgrade request includes a Content-Length header and body, which nghttpx forwards onto reusable keep-alive backend connections. The proxy re-adds the Upgrade and Connection headers while passing the Content-Length header verbatim. If the backend interprets this ambiguous message in the attacker's favor, it can lead to smuggling and cross-client response-queue poisoning.
Users can upgrade to nghttp2 version 1.69.90 or later, where this vulnerability has been fixed.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jun 29, 2026References to Advisories, Solutions, and Tools
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-444 | Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| nghttp2 nghttp2 | <= 1.69.0 |
CPE
Remediation
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Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 30, 2026 | Initial Analysis | [email protected] |
| Jun 29, 2026 | CVE Modified | CISA-ADP |
| Jun 28, 2026 | New CVE Received | [email protected] |