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2 vulnerabilities found for h2 by python-hyper

CVE-2026-71554 (GCVE-0-2026-71554)
Vulnerability from cvelistv5
Published
2026-08-06 21:46
Modified
2026-08-08 02:49
Severity ?
5.3 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CWE
  • CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
Summary
h2 is a pure-Python implementation of a HTTP/2 protocol stack. Versions up to and including 4.4.0 accept request header blocks containing more than one Host header, and forward every Host header to the consuming application. Where the consumer downgrades HTTP/2 to HTTP/1.1, the resulting request carries two Host header lines, providing a request smuggling primitive. This issue is fixed in version 4.4.1.
References
Impacted products
Vendor Product Version
python-hyper h2 Version: < 4.4.1
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CVE-2025-57804 (GCVE-0-2025-57804)
Vulnerability from cvelistv5
Published
2025-08-25 21:04
Modified
2025-11-03 18:13
Severity ?
6.9 (Medium) - 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
CWE
  • CWE-93 - Improper Neutralization of CRLF Sequences ('CRLF Injection')
Summary
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.
References
Impacted products
Vendor Product Version
python-hyper h2 Version: < 4.3.0
 Create a notification for this product.
Show details on NVD website

To clipboard 

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