Description
Squid 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.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | squid | 4.1-1 | — |
| Debian 13 | squid | 4.1-1 | — |
| Debian 12 | squid | 4.1-1 | — |
| Debian 8 | squid3 | 3.4.8-6+deb8u1 | DSA-3327-1 |
| Debian 7 | squid3 | 3.1.20-2.2+deb7u3 | DSA-3327-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 6.0 | squid3 | 3.1.6-1.2+squeeze5 | DLA-286-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | squid3 | 3.5.12-1ubuntu6 | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP1 | squid | 3.3.14-20.2 | SUSE-SU-2016:2008-1 |
| SLES 11 SP4 | squid3 | 3.1.23-8.16.30.1 | SUSE-SU-2016:2089-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP1 | squid | 3.3.14-20.2 | SUSE-SU-2016:2008-1 |
| SLES for SAP 11 SP4 | squid3 | 3.1.23-8.16.30.1 | SUSE-SU-2016:2089-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | squid | 3.5.22-1.1 | openSUSE-SU-2024:10307-1 |
Advisories 5
- DLA-286-1 squid3 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-3327-1 squid3 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2016:2008-1 Security update for squid SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2016:2089-1 Security update for squid3 SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:10307-1 squid-3.5.22-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
References
- [oss-security] 20150706 Squid HTTP proxy CVE request mailing-list
- 1032873 vdb-entry
- FEDORA-2016-7b40eb9e29 vendor-advisory
- http://www.squid-cache.org/Versions/v3/3.5/changesets/squid-3.5-13856.patch
- SUSE-SU-2016:1996 vendor-advisory
- [oss-security] 20150717 Re: Re: Squid HTTP proxy CVE request mailing-list
- [oss-security] 20150709 Re: Squid HTTP proxy CVE request mailing-list
- openSUSE-SU-2016:2081 vendor-advisory
- http://www.squid-cache.org/Versions/v3/3.1/changesets/squid-3.1-10494.patch
- [oss-security] 20150710 Re: Squid HTTP proxy CVE request mailing-list
- SUSE-SU-2016:2089 vendor-advisory
- http://www.squid-cache.org/Advisories/SQUID-2015_2.txt
- DSA-3327 vendor-advisory
- 75553 vdb-entry
- http://www.squid-cache.org/Versions/v3/3.4/changesets/squid-3.4-13225.patch