Description
The Edge Side Includes (ESI) parser in Squid 3.x before 3.5.15 and 4.x before 4.0.7 does not check buffer limits during XML parsing, which allows remote HTTP servers to cause a denial of service (assertion failure and daemon exit) via a crafted XML document, related to esi/CustomParser.cc and esi/CustomParser.h.
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.
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | squid3 | 3.5.12-1ubuntu7.5 | USN-3557-1 |
| Ubuntu 14.04 LTS | squid3 | 3.3.8-1ubuntu6.11 | USN-3557-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | squid +2 | 7:3.5.20-2.el7 | RHSA-2016:2600 |
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 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | squid +2 | 7:3.5.20-2.el7 | ELSA-2016-2600 |
Advisories 5
- RHSA-2016:2600 Red Hat Security Advisory: squid security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- USN-3557-1 squid3 vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 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
- ELSA-2016-2600 Moderate: squid security, bug fix, and enhancement update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Nov 9, 2016
References
- USN-3557-1 vendor-advisory
- GLSA-201607-01 vendor-advisory
- http://www.squid-cache.org/Advisories/SQUID-2016_2.txt
- SUSE-SU-2016:1996 vendor-advisory
- http://www.squid-cache.org/Versions/v4/changesets/squid-4-14549.patch
- RHSA-2016:2600 vendor-advisory
- openSUSE-SU-2016:2081 vendor-advisory
- http://www.squid-cache.org/Versions/v3/3.5/changesets/squid-3.5-13993.patch
- [oss-security] 20160226 Re: CVE request: Squid HTTP Caching Proxy multiple denial of service issues mailing-list
- SUSE-SU-2016:2089 vendor-advisory
- 1035101 vdb-entry