CVE-2025-57804

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Source
https://cve.org/CVERecord?id=CVE-2025-57804
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-57804.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2025-57804
Aliases
Downstream
Related
Published
2025-08-25T21:04:52.642Z
Modified
2026-04-10T05:32:40.793976Z
Severity
  • 6.9 (Medium) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N CVSS Calculator
Summary
h2 allows HTTP Request Smuggling due to illegal characters in headers
Details

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.

Database specific 
{
    "cna_assigner": "GitHub_M",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/57xxx/CVE-2025-57804.json",
    "cwe_ids": [
        "CWE-93"
    ]
}
References

Affected packages

Git / github.com/python-hyper/h2

Affected ranges

Type
GIT
Repo
https://github.com/python-hyper/h2
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
1aae569315eb170cdff00582644aca37ee38db62

Affected versions

v1.*
v1.0.0
v1.1.0
v1.1.1
v2.*
v2.0.0
v2.1.0
v2.2.0
v2.3.0
v2.4.0
v2.5.0
v2.6.0
v3.*
v3.0.0
v3.1.0
v3.1.1
v3.2.0
v4.*
v4.0.0
v4.1.0
v4.2.0

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-57804.json"