# h2 (PyPI) vulnerabilities

2 known vulnerabilities (2 medium), with the versions each affects and the releases that fix them.

## At a glance

- Latest release: not known (cve.now hasn't read this package's releases)
- Newest unaffected release: not known without release data
- Weekly downloads: 43.9M
- Dependents: 9,424
- Registry: https://pypi.org/project/h2/

## Advisories (2)

### [CVE-2026-71554](https://cve.now/CVE-2026-71554): h2: Duplicate Host header could facilitate request smuggling

- Severity: Medium 5.3
- Published: Aug 6, 2026
- Affected: fixed in 4.4.1.

### [CVE-2025-57804](https://cve.now/CVE-2025-57804): h2 allows HTTP Request Smuggling due to illegal characters in headers

- Severity: Medium 6.9
- Published: Aug 25, 2025
- Affected: fixed in 4.3.0.

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