Description

h2 is a pure-Python implementation of a HTTP/2 protocol stack. Prior to version 4.3.0, an HTTP/2 request splitting vulnerability allows attackers to perform request smuggling attacks by injecting CRLF characters into headers. This occurs when servers downgrade HTTP/2 requests to HTTP/1.1 without properly validating header names/values, enabling attackers to manipulate request boundaries and bypass security controls. This issue has been patched in version 4.3.0.

INFO

Published Date :

2025-08-25T21:04:52.642Z

Last Modified :

2025-11-03T18:13:44.839Z

Source :

GitHub_M
AFFECTED PRODUCTS

The following products are affected by CVE-2025-57804 vulnerability.

Vendors Products
Hyper
  • H2
REFERENCES

Here, you will find a curated list of external links that provide in-depth information to CVE-2025-57804.

URL Resource
https://github.com/python-hyper/h2/commit/035e9899f95e3709af098f578bfc3cd302298e3a cve-icon cve-icon cve-icon
https://github.com/python-hyper/h2/security/advisories/GHSA-847f-9342-265h cve-icon cve-icon cve-icon
https://lists.debian.org/debian-lts-announce/2025/09/msg00004.html cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2025-57804 cve-icon
https://www.cve.org/CVERecord?id=CVE-2025-57804 cve-icon
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CVSS Vulnerability Scoring System

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Detailed values of each vector for above chart.
Attack Vector
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User Interaction
Scope
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Integrity Impact
Availability Impact