CVE-2016-4553
client_side.cc in Squid before 3.5.18 and 4.x before 4.0.10 does not properly ignore the Host...
CVE-2016-4553 is a high vulnerability (CVSS 8.6) in Squid-cache Squid, published May 10, 2016. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 80.0%, the 99th percentile. Fixed in squid3 3.4.8-6+deb8u3.
client_side.cc in Squid before 3.5.18 and 4.x before 4.0.10 does not properly ignore the Host header when absolute-URI is provided, which allows remote attackers to conduct cache-poisoning attacks via an HTTP request.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
NVD Score used
8.6
client_side.cc in Squid before 3.5.18 and 4.x before 4.0.10 does not properly ignore the Host header when absolute-URI is provided, which allows remote attackers to conduct cache-poisoning attacks via an HTTP request.
- Record
CVE-2016-4553- CVSS 3.0
- 8.6 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N - CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:N/I:P/A:N - Weakness
- CWE-345
- Updated
- 2026-11-02
CVE List No score
client_side.cc in Squid before 3.5.18 and 4.x before 4.0.10 does not properly ignore the Host header when absolute-URI is provided, which allows remote attackers to conduct cache-poisoning attacks via an HTTP request.
- Record
CVE-2016-4553- Updated
- 2026-11-02
EUVDEUVD-2016-5540 No score
client_side.cc in Squid before 3.5.18 and 4.x before 4.0.10 does not properly ignore the Host header when absolute-URI is provided, which allows remote attackers to conduct cache-poisoning attacks via an HTTP request.
- Record
EUVD-2016-5540- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-p6vj-j24g-56wp
8.6
client_side.cc in Squid before 3.5.18 and 4.x before 4.0.10 does not properly ignore the Host...
client_side.cc in Squid before 3.5.18 and 4.x before 4.0.10 does not properly ignore the Host header when absolute-URI is provided, which allows remote attackers to conduct cache-poisoning attacks via an HTTP request.
- Record
GHSA-p6vj-j24g-56wp- CVSS 3.0
- 8.6 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N - Weakness
- CWE-345
- Updated
- 2026-11-02
OSV
8.6
client_side.cc in Squid before 3.5.18 and 4.x before 4.0.10 does not properly ignore the Host header when absolute-URI is provided, which allows remote attackers to conduct cache-poisoning attacks via an HTTP request.
- Record
CVE-2016-4553- CVSS 3.0
- 8.6 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N - Updated
- 2026-11-02
OSVUBUNTU-CVE-2016-4553
8.6
client_side.cc in Squid before 3.5.18 and 4.x before 4.0.10 does not properly ignore the Host header when absolute-URI is provided, which allows remote attackers to conduct cache-poisoning attacks via an HTTP request.
- Record
UBUNTU-CVE-2016-4553- CVSS 3.0
- 8.6 High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N - Updated
- 2026-11-02
Show 5 moreShow less
OSVMGASA-2016-0171 No score
Updated squid packages fix security vulnerability
Due to incorrect data validation of intercepted HTTP Request messages Squid is vulnerable to clients bypassing the protection against CVE-2009-0801 related issues. This leads to cache poisoning. This allows any client, including browser scripts, to bypass local security and poison the proxy cache and any downstream caches with content from an arbitrary source (CVE-2016-4553).
Due to incorrect input validation Squid is vulnerable to a header smuggling attack leading to cache poisoning and to bypass of same-origin security policy in Squid and some client browsers (CVE-2016-4554).
- Record
MGASA-2016-0171- Updated
- 2026-11-02
OSVopenSUSE-SU-2024:11403-1 No score
squid-4.16-1.5 on GA media
These are all security issues fixed in the squid-4.16-1.5 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2024:11403-1- Updated
- 2026-11-02
OSVSUSE-SU-2016:2008-1 No score
Security update for squid
The Squid HTTP proxy has been updated to version 3.3.14, fixing the following security issues:
- Fixed multiple Denial of Service issues in HTTP Response processing. (CVE-2016-2569, CVE-2016-2570, CVE-2016-2571, CVE-2016-2572, bsc#968392, bsc#968393, bsc#968394, bsc#968395)
- CVE-2016-3947: Buffer overrun issue in pinger ICMPv6 processing. (bsc#973782)
- CVE-2015-5400: Improper protection of alternate path. (bsc#938715)
- CVE-2015-3455: Squid http proxy configured with client-first SSL bumping did not correctly validate server certificate. (bsc#929493)
- CVE-2016-3948: Fixed denial of service in HTTP Response processing (bsc#973783)
- CVE-2016-4051: fixes buffer overflow in cachemgr.cgi (bsc#976553)
- CVE-2016-4052, CVE-2016-4053, CVE-2016-4054: Fixed multiple issues in ESI processing (bsc#976556)
- CVE-2016-4553: Fixed cache poisoning issue in HTTP Request handling (bsc#979009)
- CVE-2016-4554: Fixed header smuggling issue in HTTP Request processing (bsc#979010)
- Fixed multiple Denial of Service issues in ESI Response processing. (CVE-2016-4555, CVE-2016-4556, bsc#979011, bsc#979008)
Additionally, the following non-security issues have been fixed:
- Fix header size in script unsquid.pl. (bsc#902197)
- Add external helper ext_session_acl to package. (bsc#959290)
- Update forward_max_tries to permit 25 server paths With cloud sites becoming more popular more CDN servers are producing long lists of IPv6 and IPv4 addresses. If there are not enough paths selected the IPv4 ones may never be reached.
- squid.init: wait that squid really dies when we kill it on upgrade instead of proclaiming its demise prematurely (bnc#963539)
- Record
SUSE-SU-2016:2008-1- Updated
- 2026-11-02
OSVSUSE-SU-2016:2089-1 No score
Security update for squid3
This update for squid3 fixes the following issues:
-
Multiple issues in pinger ICMP processing. (CVE-2014-7141, CVE-2014-7142)
-
CVE-2016-3947: Buffer overrun issue in pinger ICMPv6 processing. (bsc#973782)
-
CVE-2016-4554: fix header smuggling issue in HTTP Request processing (bsc#979010)
-
Fix multiple Denial of Service issues in HTTP Response processing. (CVE-2016-2569, CVE-2016-2570, CVE-2016-2571, CVE-2016-2572, bsc#968392, bsc#968393, bsc#968394, bsc#968395)
-
Regression caused by the DoS fixes above (bsc#993299)
-
CVE-2016-3948: Fix denial of service in HTTP Response processing (bsc#973783)
-
CVE-2016-4051: fixes buffer overflow in cachemgr.cgi (bsc#976553)
-
CVE-2016-4052, CVE-2016-4053, CVE-2016-4054:
- fixes multiple issues in ESI processing (bsc#976556)
-
CVE-2016-4556: fixes double free vulnerability in Esi.cc (bsc#979008)
-
CVE-2015-5400: Improper Protection of Alternate Path (bsc#938715)
-
CVE-2014-6270: fix off-by-one in snmp subsystem (bsc#895773)
-
Memory leak in squid3 when using external_acl (bsc#976708)
- Record
SUSE-SU-2016:2089-1- Updated
- 2026-11-02
OSVUSN-2995-1 No score
squid3 vulnerabilities
Yuriy M. Kaminskiy discovered that the Squid pinger utility incorrectly handled certain ICMPv6 packets. A remote attacker could use this issue to cause Squid to crash, resulting in a denial of service, or possibly cause Squid to leak information into log files. (CVE-2016-3947)
Yuriy M. Kaminskiy discovered that the Squid cachemgr.cgi tool incorrectly handled certain crafted data. A remote attacker could use this issue to cause Squid to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2016-4051)
It was discovered that Squid incorrectly handled certain Edge Side Includes (ESI) responses. A remote attacker could possibly use this issue to cause Squid to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2016-4052, CVE-2016-4053, CVE-2016-4054)
Jianjun Chen discovered that Squid did not correctly ignore the Host header when absolute-URI is provided. A remote attacker could possibly use this issue to conduct cache-poisoning attacks. This issue only affected Ubuntu 14.04 LTS, Ubuntu 15.10 and Ubuntu 16.04 LTS. (CVE-2016-4553)
Jianjun Chen discovered that Squid incorrectly handled certain HTTP Host headers. A remote attacker could possibly use this issue to conduct cache-poisoning attacks. (CVE-2016-4554)
It was discovered that Squid incorrectly handled certain Edge Side Includes (ESI) responses. A remote attacker could possibly use this issue to cause Squid to crash, resulting in a denial of service. (CVE-2016-4555, CVE-2016-4556)
- Record
USN-2995-1- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
squid3Debian:8 |
before 3.4.8-6+deb8u3, plus listed versions 3.4.8-63.4.8-6+deb8u13.4.8-6+deb8u23.4.8-6+deb8u2~bpo70+1 |
3.4.8-6+deb8u3 |
squidMageia:5 |
before 3.5.19-1.mga5 | 3.5.19-1.mga5 |
squidRed Hat:enterprise_linux:7::server |
before 7:3.3.8-26.el7_2.3 | 7:3.3.8-26.el7_2.3 |
squid-debuginfoRed Hat:enterprise_linux:7::server |
before 7:3.3.8-26.el7_2.3 | 7:3.3.8-26.el7_2.3 |
squid-sysvinitRed Hat:enterprise_linux:7::server |
before 7:3.3.8-26.el7_2.3 | 7:3.3.8-26.el7_2.3 |
squidRed Hat:enterprise_linux:7::workstation |
before 7:3.3.8-26.el7_2.3 | 7:3.3.8-26.el7_2.3 |
squid-debuginfoRed Hat:enterprise_linux:7::workstation |
before 7:3.3.8-26.el7_2.3 | 7:3.3.8-26.el7_2.3 |
squid-sysvinitRed Hat:enterprise_linux:7::workstation |
before 7:3.3.8-26.el7_2.3 | 7:3.3.8-26.el7_2.3 |
squid34Red Hat:enterprise_linux:6::server |
before 7:3.4.14-9.el6_8.3 | 7:3.4.14-9.el6_8.3 |
squid34-debuginfoRed Hat:enterprise_linux:6::server |
before 7:3.4.14-9.el6_8.3 | 7:3.4.14-9.el6_8.3 |
Show 9 moreShow less
| Package | Affected | Fixed |
|---|---|---|
squid34Red Hat:enterprise_linux:6::workstation |
before 7:3.4.14-9.el6_8.3 | 7:3.4.14-9.el6_8.3 |
squid34-debuginfoRed Hat:enterprise_linux:6::workstation |
before 7:3.4.14-9.el6_8.3 | 7:3.4.14-9.el6_8.3 |
squidSUSE:Linux Enterprise Server 12 SP1 |
before 3.3.14-20.2 | 3.3.14-20.2 |
squidSUSE:Linux Enterprise Server for SAP Applications 12 SP1 |
before 3.3.14-20.2 | 3.3.14-20.2 |
squid3SUSE:Linux Enterprise Server 11 SP4 |
before 3.1.23-8.16.30.1 | 3.1.23-8.16.30.1 |
squid3SUSE:Linux Enterprise Server for SAP Applications 11 SP4 |
before 3.1.23-8.16.30.1 | 3.1.23-8.16.30.1 |
squid3Ubuntu:14.04:LTS |
before 3.3.8-1ubuntu6.8, plus listed versions 3.3.8-1ubuntu33.3.8-1ubuntu43.3.8-1ubuntu53.3.8-1ubuntu63.3.8-1ubuntu6.1 Show 4 moreShow less3.3.8-1ubuntu6.23.3.8-1ubuntu6.33.3.8-1ubuntu6.43.3.8-1ubuntu6.6 |
3.3.8-1ubuntu6.8 |
squid3Ubuntu:16.04:LTS |
before 3.5.12-1ubuntu7.2, plus listed versions 3.3.8-1ubuntu163.3.8-1ubuntu173.5.12-1ubuntu63.5.12-1ubuntu73.5.12-1ubuntu7.1 |
3.5.12-1ubuntu7.2 |
squidopenSUSE:Tumbleweed |
before 4.16-1.5 | 4.16-1.5 |
History
| When | Changed | Sources |
|---|---|---|
| 2026-11-03 | aliases | EUVD |
| 2026-11-02 | created | CVE List, GitHub Advisories, NVD, OSV |
References
security.gentoo.org/glsa/201607-01
oracle.com/technetwork/topics/security/linuxbulletinapr2016-2952096.html
bugs.squid-cache.org/show_bug.cgi?id=4501
lists.opensuse.org/opensuse-security-announce/2016-08/msg00010.html
squid-cache.org/Advisories/SQUID-2016_7.txt
ubuntu.com/usn/USN-2995-1
Show 140 moreShow less
squid-cache.org/Versions/v3/3.5/changesets/squid-3.5-14039.patch
access.redhat.com/errata/RHSA-2016:1140
lists.opensuse.org/opensuse-updates/2016-08/msg00069.html
access.redhat.com/errata/RHSA-2016:1139
lists.opensuse.org/opensuse-security-announce/2016-08/msg00040.html
securitytracker.com/id/1035768
debian.org/security/2016/dsa-3625
nvd.nist.gov/vuln/detail/CVE-2016-4553
github.com/advisories/GHSA-p6vj-j24g-56wp
advisories.mageia.org/MGASA-2016-0171.html
bugs.mageia.org/show_bug.cgi?id=18388
squid-cache.org/Advisories/SQUID-2016_8.txt
access.redhat.com/security/updates/classification
squid-cache.org/Advisories/SQUID-2016_5.txt
squid-cache.org/Advisories/SQUID-2016_6.txt
squid-cache.org/Advisories/SQUID-2016_9.txt
bugzilla.redhat.com/show_bug.cgi?id=1329126
bugzilla.redhat.com/show_bug.cgi?id=1329136
bugzilla.redhat.com/show_bug.cgi?id=1334233
bugzilla.redhat.com/show_bug.cgi?id=1334241
bugzilla.redhat.com/show_bug.cgi?id=1334246
bugzilla.redhat.com/show_bug.cgi?id=1334786
security.access.redhat.com/data/csaf/v2/advisories/2016/rhsa-2016_1139.json
access.redhat.com/security/cve/CVE-2016-4051
cve.org/CVERecord?id=CVE-2016-4051
nvd.nist.gov/vuln/detail/CVE-2016-4051
access.redhat.com/security/cve/CVE-2016-4052
cve.org/CVERecord?id=CVE-2016-4052
nvd.nist.gov/vuln/detail/CVE-2016-4052
access.redhat.com/security/cve/CVE-2016-4053
cve.org/CVERecord?id=CVE-2016-4053
nvd.nist.gov/vuln/detail/CVE-2016-4053
access.redhat.com/security/cve/CVE-2016-4054
cve.org/CVERecord?id=CVE-2016-4054
nvd.nist.gov/vuln/detail/CVE-2016-4054
access.redhat.com/security/cve/CVE-2016-4553
cve.org/CVERecord?id=CVE-2016-4553
access.redhat.com/security/cve/CVE-2016-4554
cve.org/CVERecord?id=CVE-2016-4554
nvd.nist.gov/vuln/detail/CVE-2016-4554
access.redhat.com/security/cve/CVE-2016-4555
cve.org/CVERecord?id=CVE-2016-4555
nvd.nist.gov/vuln/detail/CVE-2016-4555
access.redhat.com/security/cve/CVE-2016-4556
cve.org/CVERecord?id=CVE-2016-4556
nvd.nist.gov/vuln/detail/CVE-2016-4556
security.access.redhat.com/data/csaf/v2/advisories/2016/rhsa-2016_1140.json
suse.com/support/update/announcement/2016/suse-su-20162008-1
bugzilla.suse.com/902197
bugzilla.suse.com/929493
bugzilla.suse.com/938715
bugzilla.suse.com/955783
bugzilla.suse.com/959290
bugzilla.suse.com/963539
bugzilla.suse.com/968392
bugzilla.suse.com/968393
bugzilla.suse.com/968394
bugzilla.suse.com/968395
bugzilla.suse.com/973782
bugzilla.suse.com/973783
bugzilla.suse.com/976553
bugzilla.suse.com/976556
bugzilla.suse.com/979008
bugzilla.suse.com/979009
bugzilla.suse.com/979010
bugzilla.suse.com/979011
suse.com/security/cve/CVE-2015-3455
suse.com/security/cve/CVE-2015-5400
suse.com/security/cve/CVE-2016-2569
suse.com/security/cve/CVE-2016-2570
suse.com/security/cve/CVE-2016-2571
suse.com/security/cve/CVE-2016-2572
suse.com/security/cve/CVE-2016-3947
suse.com/security/cve/CVE-2016-3948
suse.com/security/cve/CVE-2016-4051
suse.com/security/cve/CVE-2016-4052
suse.com/security/cve/CVE-2016-4053
suse.com/security/cve/CVE-2016-4054
suse.com/security/cve/CVE-2016-4553
suse.com/security/cve/CVE-2016-4554
suse.com/security/cve/CVE-2016-4555
suse.com/security/cve/CVE-2016-4556
suse.com/support/update/announcement/2016/suse-su-20162089-1
bugzilla.suse.com/895773
bugzilla.suse.com/967011
bugzilla.suse.com/976708
bugzilla.suse.com/993299
suse.com/security/cve/CVE-2011-3205
suse.com/security/cve/CVE-2011-4096
suse.com/security/cve/CVE-2012-5643
suse.com/security/cve/CVE-2013-0188
suse.com/security/cve/CVE-2013-4115
suse.com/security/cve/CVE-2014-0128
suse.com/security/cve/CVE-2014-6270
suse.com/security/cve/CVE-2014-7141
suse.com/security/cve/CVE-2014-7142
suse.com/security/cve/CVE-2016-2390
ubuntu.com/security/CVE-2016-4553
ubuntu.com/security/notices/USN-2995-1
ubuntu.com/security/CVE-2016-3947
ubuntu.com/security/CVE-2016-4051
ubuntu.com/security/CVE-2016-4052
ubuntu.com/security/CVE-2016-4053
ubuntu.com/security/CVE-2016-4054
ubuntu.com/security/CVE-2016-4554
ubuntu.com/security/CVE-2016-4555
ubuntu.com/security/CVE-2016-4556
suse.com/security/cve/CVE-2016-10002
suse.com/security/cve/CVE-2016-10003
suse.com/security/cve/CVE-2018-1000024
suse.com/security/cve/CVE-2018-1000027
suse.com/security/cve/CVE-2018-1172
suse.com/security/cve/CVE-2018-19131
suse.com/security/cve/CVE-2018-19132
suse.com/security/cve/CVE-2019-12519
suse.com/security/cve/CVE-2019-12523
suse.com/security/cve/CVE-2019-12525
suse.com/security/cve/CVE-2019-12526
suse.com/security/cve/CVE-2019-12527
suse.com/security/cve/CVE-2019-12528
suse.com/security/cve/CVE-2019-12529
suse.com/security/cve/CVE-2019-12854
suse.com/security/cve/CVE-2019-13345
suse.com/security/cve/CVE-2019-18677
suse.com/security/cve/CVE-2019-18678
suse.com/security/cve/CVE-2019-18679
suse.com/security/cve/CVE-2019-18860
suse.com/security/cve/CVE-2020-11945
suse.com/security/cve/CVE-2020-14059
suse.com/security/cve/CVE-2020-15049
suse.com/security/cve/CVE-2020-15810
suse.com/security/cve/CVE-2020-15811
suse.com/security/cve/CVE-2020-24606
suse.com/security/cve/CVE-2020-25097
suse.com/security/cve/CVE-2020-8449
suse.com/security/cve/CVE-2020-8517
suse.com/security/cve/CVE-2021-28651
suse.com/security/cve/CVE-2021-28652
suse.com/security/cve/CVE-2021-28662
suse.com/security/cve/CVE-2021-31806