python3-h11: h11 is a Python implementation of HTTP/1.1
CVE-2025-43859 is fixed in 2 products on 1 platform, first by python3-h11 0.14.0-1ubuntu0.24.04.1, released April 24, 2025. It is not reported as exploited. Patch Radar priority: High.
h11 is a Python implementation of HTTP/1.1. Prior to version 0.16.0, aleniency in h11's parsing of line terminators in chunked-coding messagebodies can lead to request smuggling vulnerabilities under certainconditions. This issue has been patched in version 0.16.0. Sinceexploitation requires the combination of buggy h11 with a buggy (reverse)proxy, fixing either component is sufficient to mitigate this issue.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| python-h11 · Debian 12.15 (bookworm) | 0.14.0-1.1~deb12u1 | DEBIAN-CVE-2025-43859 | Apr 24, 2025 |
| python-h11 · Debian 13.5 (trixie) | 0.14.0-1.1 | DEBIAN-CVE-2025-43859 | Apr 24, 2025 |
| python-h11 · Debian 14 | 0.14.0-1.1 | DEBIAN-CVE-2025-43859 | Apr 24, 2025 |
| python-h11 · opensuse-leap 15.6 | 0.14.0-150400.9.6.1 | SUSE-SU-2025:1430-1 | May 2, 2025 |
| python-h11 · sles 15.6 | 0.14.0-150400.9.6.1 | SUSE-SU-2025:1430-1 | May 2, 2025 |
| python3-h11 · Ubuntu 24.04.5 LTS (noble) | 0.14.0-1ubuntu0.24.04.1 | python3-h11 0.14.0-1ubuntu0.24.04.1 | Apr 24, 2025 |
| python3-h11 · Ubuntu 24.10 (oracular) | 0.14.0-1ubuntu0.24.10.1 | python3-h11 0.14.0-1ubuntu0.24.10.1 | Jan 16, 2026 |
| python3-h11 · Ubuntu 25.04 (plucky) | 0.14.0-1ubuntu0.25.04.1 | python3-h11 0.14.0-1ubuntu0.25.04.1 | Jan 16, 2026 |
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