Description
Squid 3.x before 3.5.15 and 4.x before 4.0.7 does not properly append data to String objects, which allows remote servers to cause a denial of service (assertion failure and daemon exit) via a long string, as demonstrated by a crafted HTTP Vary header.
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 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | squid | 4.16-1.5 | openSUSE-SU-2024:11403-1 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | squid +2 | 7:3.5.20-2.el7 | ELSA-2016-2600 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
GitHub 1 repository
-
amit-raut/CVE-2016-2569 ★ 6 · Feb 3, 2018
Squid 3.x before 3.5.15 and 4.x before 4.0.7 does not properly append data to String objects, which allows remote servers to cause a denial of service (assertion failure and daemon exit) via a long s…
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 6
- 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
- openSUSE-SU-2024:11403-1 squid-4.16-1.5 on GA media 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
- RHSA-2016:2600 vendor-advisory
- http://www.squid-cache.org/Versions/v4/changesets/squid-4-14552.patch
- openSUSE-SU-2016:2081 vendor-advisory
- http://www.squid-cache.org/Versions/v3/3.5/changesets/squid-3.5-13991.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