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Debian LTS Advisory DLA-3851-1                debian-lts@lists.debian.org
https://www.debian.org/lts/security/                      Markus Koschany
June 30, 2024                                 https://wiki.debian.org/LTS
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Package        : gunicorn
Version        : 19.9.0-1+deb10u1
CVE ID         : CVE-2024-1135
Debian Bug     : 1069126

Gunicorn, an event-based HTTP/WSGI server, fails to properly validate Transfer-
Encoding headers, leading to HTTP Request Smuggling (HRS) vulnerabilities. By
crafting requests with conflicting Transfer-Encoding headers, attackers can
bypass security restrictions and access restricted endpoints. This issue is due
to Gunicorn’s handling of Transfer-Encoding headers, where it incorrectly
processes requests with multiple, conflicting Transfer-Encoding headers,
treating them as chunked regardless of the final encoding specified. This
vulnerability allows for a range of attacks including cache poisoning, session
manipulation, and data exposure.

For Debian 10 buster, this problem has been fixed in version
19.9.0-1+deb10u1.

We recommend that you upgrade your gunicorn packages.

For the detailed security status of gunicorn please refer to
its security tracker page at:
https://security-tracker.debian.org/tracker/gunicorn

Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://wiki.debian.org/LTS