Description
Squid 3.2.x before 3.2.14, 3.3.x before 3.3.14, 3.4.x before 3.4.13, and 3.5.x before 3.5.4, when configured with client-first SSL-bump, do not properly validate the domain or hostname fields of X.509 certificates, which allows man-in-the-middle attackers to spoof SSL servers via a valid certificate.
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 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 14.04 LTS | squid3 | 3.3.8-1ubuntu6.6 | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | squid +1 | 7:3.3.8-26.el7 | RHSA-2015:2378 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP1 | squid | 3.3.14-20.2 | SUSE-SU-2016:2008-1 |
Show 1 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 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | squid +1 | 7:3.3.8-26.el7 | ELSA-2015-2378 |
Advisories 3
- RHSA-2015:2378 Red Hat Security Advisory: squid security and bug fix update Red Hat Security Advisories (RHSA) · Jun 27, 2026
- SUSE-SU-2016:2008-1 Security update for squid SUSE / openSUSE Security Updates · Feb 4, 2026
- ELSA-2015-2378 Moderate: squid security and bug fix update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Nov 23, 2015
References
- FEDORA-2016-7b40eb9e29 vendor-advisory
- RHSA-2015:2378 vendor-advisory
- http://www.oracle.com/technetwork/topics/security/bulletinjul2015-2511963.html
- openSUSE-SU-2015:1546 vendor-advisory
- 74438 vdb-entry
- http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2015-2719645.html
- 1032221 vdb-entry
- openSUSE-SU-2016:2081 vendor-advisory
- http://advisories.mageia.org/MGASA-2015-0191.html
- MDVSA-2015:230 vendor-advisory
- http://www.squid-cache.org/Advisories/SQUID-2015_1.txt