CVE-2025-57804 · cross-distro fix matrix

CVE-2025-57804: 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 pro

Affects 1 Linux release across 1 (distro × package) combinations.

Fix per ecosystem

Each block below is a distro release where CVE-2025-57804 has a known fix. Run the listed command on that distro to remediate.

Debian bullseye

Source: Debian Security Tracker

python-h2→ fixed in4.0.0-3+deb11u1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y python-h2
```

Are YOU affected by CVE-2025-57804?

5-second check on your actual server. Reads /etc/os-release, uname -r, and the distro's package manager; matches against this same cross-source index live.

curl https://mindsparkstack.com/scan.sh | bash

Form-based quickscan View on NVD

Continuous monitoring beats manual checking

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