Debian Security Advisory

DSA-4960-1 haproxy -- security update

Date Reported:
17 Aug 2021
Affected Packages:
Security database references:
In Mitre's CVE dictionary: CVE-2021-39240, CVE-2021-39241, CVE-2021-39242.
More information:

Several vulnerabilities were discovered in HAProxy, a fast and reliable load balancing reverse proxy, which can result in HTTP request smuggling. By carefully crafting HTTP/2 requests, it is possible to smuggle another HTTP request to the backend selected by the HTTP/2 request. With certain configurations, it allows an attacker to send an HTTP request to a backend, circumventing the backend selection logic.

Known workarounds are to disable HTTP/2 and set "tune.h2.max-concurrent-streams" to 0 in the global section.

global tune.h2.max-concurrent-streams 0

For the stable distribution (bullseye), these problems have been fixed in version 2.2.9-2+deb11u1.

We recommend that you upgrade your haproxy packages.

For the detailed security status of haproxy please refer to its security tracker page at: