CVE-2025-43859

Source
https://nvd.nist.gov/vuln/detail/CVE-2025-43859
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-43859.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2025-43859
Aliases
Related
Published
2025-04-24T19:15:47Z
Modified
2025-05-09T05:45:38.907921Z
Downstream
Summary
[none]
Details

h11 is a Python implementation of HTTP/1.1. Prior to version 0.16.0, a leniency in h11's parsing of line terminators in chunked-coding message bodies can lead to request smuggling vulnerabilities under certain conditions. This issue has been patched in version 0.16.0. Since exploitation requires the combination of buggy h11 with a buggy (reverse) proxy, fixing either component is sufficient to mitigate this issue.

References

Affected packages

Debian:12 / python-h11

Package

Name
python-h11
Purl
pkg:deb/debian/python-h11?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected

Affected versions

0.*

0.14.0-1
0.14.0-1.1~deb12u1
0.14.0-1.1

Ecosystem specific

{
    "urgency": "not yet assigned"
}

Debian:13 / python-h11

Package

Name
python-h11
Purl
pkg:deb/debian/python-h11?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
0.14.0-1.1

Affected versions

0.*

0.14.0-1
0.14.0-1.1~deb12u1

Ecosystem specific

{
    "urgency": "not yet assigned"
}

Git / github.com/python-hyper/h11

Affected ranges

Type
GIT
Repo
https://github.com/python-hyper/h11
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed

Affected versions

v0.*

v0.11.0
v0.12.0
v0.13.0
v0.14.0
v0.15.0
v0.5.0
v0.6.0
v0.7.0
v0.8.0
v0.8.1
v0.9.0