DescriptionSquid before 3.5.6 does not properly handle CONNECT method peer responses when configured with cache_peer, which allows remote attackers to bypass intended restrictions and gain access to a backend proxy via a CONNECT request.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)
ReferencesDLA-286-1, DSA-3327-1
NVD severitymedium
Debian Bugs793128

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
squid (PTS)buster4.6-1+deb10u4fixed
buster (security)4.6-1+deb10u5fixed
bullseye, sid4.13-9fixed
squid3 (PTS)stretch3.5.23-5+deb9u1fixed
stretch (security)3.5.23-5+deb9u6fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs


[wheezy] - squid <no-dsa> (Fix is hard to backport and default configuration is not affected)
[squeeze] - squid <no-dsa> (Fix is hard to backport and default configuration is not affected) (3.5) (3.4)
In squeeze's squid3 the code is structured differently but the bug still appears to be present.
For squid 2.x all versions are affected, cf. comment by upstream in

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