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.
Published: 2026-06-28
Score: 6.3 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Ubuntu USN Ubuntu USN USN-8495-1 nghttp2 vulnerability
History

Tue, 21 Jul 2026 00:15:00 +0000

Type Values Removed Values Added
First Time appeared Redhat
Redhat hummingbird
CPEs cpe:/a:redhat:hummingbird:1
Vendors & Products Redhat
Redhat hummingbird
References
Metrics threat_severity

None

threat_severity

Moderate


Mon, 29 Jun 2026 15:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Sun, 28 Jun 2026 02:15:00 +0000

Type Values Removed Values Added
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.
Title nghttp2 nghttpx - HTTP Request/Response Smuggling via Upgrade Request with Content-Length
First Time appeared Nghttp2
Nghttp2 nghttp2
Weaknesses CWE-444
CPEs cpe:2.3:a:nghttp2:nghttp2:*:*:*:*:*:*:*:*
Vendors & Products Nghttp2
Nghttp2 nghttp2
References
Metrics cvssV3_1

{'score': 5.4, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N'}

cvssV4_0

{'score': 6.3, 'vector': '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'}


Subscriptions

Nghttp2 Nghttp2
Redhat Hummingbird
cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-06-29T13:51:59.891Z

Reserved: 2026-06-28T00:55:25.426Z

Link: CVE-2026-58055

cve-icon Vulnrichment

Updated: 2026-06-29T13:51:56.386Z

cve-icon NVD

No data.

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-06-28T01:32:57Z

Links: CVE-2026-58055 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-06-28T07:30:06Z

Weaknesses