CVE-2025-57804— h2 allows HTTP Request Smuggling due to illegal characters in headers
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I. Basic Information for CVE-2025-57804
Vulnerability Information
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Vulnerability Title
h2 allows HTTP Request Smuggling due to illegal characters in headers
Source: NVD (National Vulnerability Database)
Vulnerability 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.
Source: NVD (National Vulnerability Database)
CVSS Information
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Type
对CRLF序列的转义处理不恰当(CRLF注入)
Source: NVD (National Vulnerability Database)
Vulnerability Title
python-hyper h2 注入漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
python-hyper h2是Hyper开源的一个Python HTTP/2的协议实现。 python-hyper h2 4.3.0之前版本存在注入漏洞，该漏洞源于HTTP2请求拆分，可能导致请求走私攻击。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| python-hyper | h2 | < 4.3.0 | - |
II. Public POCs for CVE-2025-57804
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|---|
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IV. Related Vulnerabilities
Same product: h2
Same weakness: CWE-93
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Sandboxie-Plus privilege escalation via INI CRLF injection b
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