nghttp2 up to 1.69.0 HTTP Request request smuggling

Summaryinfo

A vulnerability identified as problematic has been detected in nghttp2 up to 1.69.0. This vulnerability affects unknown code of the component HTTP Request Handler. This manipulation causes request smuggling. The identification of this vulnerability is CVE-2026-58055. It is possible to initiate the attack remotely. Furthermore, there is an exploit available. Applying a patch is the recommended action to fix this issue.

Detailsinfo

A vulnerability classified as problematic was found in nghttp2 up to 1.69.0. Affected by this vulnerability is some unknown functionality of the component HTTP Request Handler. The manipulation with an unknown input leads to a request smuggling vulnerability. The CWE definition for the vulnerability is CWE-444. The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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.

The weakness was shared by ashdfrkl. The advisory is shared at github.com. This vulnerability is known as CVE-2026-58055 since 06/28/2026. The exploitation appears to be difficult. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are unknown but a public exploit is available.

It is possible to download the exploit at github.com. It is declared as proof-of-concept.

Applying the patch ab28105c4a0197da24f8bfc414bc116055249e1e is able to eliminate this problem. The bugfix is ready for download at github.com.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-39975). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Name

• nghttp2

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9
• 1.10
• 1.11
• 1.12
• 1.13
• 1.14
• 1.15
• 1.16
• 1.17
• 1.18
• 1.19
• 1.20
• 1.21
• 1.22
• 1.23
• 1.24
• 1.25
• 1.26
• 1.27
• 1.28
• 1.29
• 1.30
• 1.31
• 1.32
• 1.33
• 1.34
• 1.35
• 1.36
• 1.37
• 1.38
• 1.39
• 1.40
• 1.41
• 1.42
• 1.43
• 1.44
• 1.45
• 1.46
• 1.47
• 1.48
• 1.49
• 1.50
• 1.51
• 1.52
• 1.53
• 1.54
• 1.55
• 1.56
• 1.57
• 1.58
• 1.59
• 1.60
• 1.61
• 1.62
• 1.63
• 1.64
• 1.65
• 1.66
• 1.67
• 1.68
• 1.69.0

License

• open-source

Website

• Product: https://github.com/nghttp2/nghttp2/

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If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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