CVE-2026-58055
nghttp2 nghttpx - HTTP Request/Response Smuggling via Upgrade Request with Content-Length
- State
- Published
- Severity
- 6.3 Medium
- Published
- Jun 28, 2026
- Updated
- Jun 29, 2026
- Reserved
- Jun 28, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 6.3 Medium | CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:L/SA:N | VulnCheck |
| 3.1 | 5.4 Medium | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N | VulnCheck |
Weaknesses
- CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
Affected Products
| Product | Versions |
|---|---|
nghttp2nghttp2 |
|
References
- Proof of Conceptexploitthird-party-advisory
- Fix commit (master)patch
- VulnCheck Advisory: nghttp2 nghttpx - HTTP Request/Response Smuggling via Upgrade Request with Content-Lengththird-party-advisory
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