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CVE-2016-4052

34
FAUCET Score

CVE-2016-4052 is a high-severity vulnerability (CVSS 8.1) affecting Squid 3.x and 4.x versions, where multiple stack-based buffer overflows can be triggered by remote HTTP servers sending crafted Edge Side Includes (ESI) responses. This allows an unauthenticated attacker to cause a denial of service or execute arbitrary code on affected systems, though the attack complexity is high. While there is no evidence of active exploitation in the wild and no public exploit code is available, the vulnerability has garnered some community discussion.

Impacted Technologies

VendorProductVersion(s)CPE
12.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:12.04:*:*:*:lts:*:*:*
14.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:*
15.10CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:15.10:*:*:*:*:*:*:*
16.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*
3.0CPE matchmatch criteria
cpe:2.3:a:squid-cache:squid:3.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

8.1HIGH

CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
2.2
Impact Score
5.9
CvssVersion
3.0

Exploit Intelligence

EPSS Score
12.87%
Probability of exploitation in next 30 days
EPSS Percentile
95.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-24
Model: v2026.06.15
This CVE's current EPSS score of 0.1287 is in the 78th percentile among its peer group of 8,913 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (4)

oraclepatch availablevia nvd_reference
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: squid-7:3.1.23-16.el6_8.4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: squid34-7:3.4.14-9.el6_8.3
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: squid-7:3.3.8-26.el7_2.3
View patch

Vendor Advisories (1)

redhatCVE-2016-4052Moderate

squid: multiple issues in ESI processing

Apr 20, 2016

References

lists.opensuse.org / opensuse-security-announce/2016-08/msg00010.html
lists.opensuse.org / opensuse-security-announce/2016-08/msg00040.html
lists.opensuse.org / opensuse-updates/2016-08/msg00069.html
access.redhat.com / errata/RHSA-2016:1138
access.redhat.com / errata/RHSA-2016:1139
access.redhat.com / errata/RHSA-2016:1140
security.gentoo.org / glsa/201607-01
debian.org / security/2016/dsa-3625
openwall.com / lists/oss-security/2016/04/20/6
Mailing ListThird Party Advisory
openwall.com / lists/oss-security/2016/04/20/9
Mailing ListThird Party Advisory
oracle.com / technetwork/security-advisory/cpujul2016-2881720.html
PatchThird Party Advisory
oracle.com / technetwork/topics/security/linuxbulletinapr2016-2952096.html
securityfocus.com / bid/86788
securityfocus.com / bid/91787
Third Party AdvisoryVDB Entry
securitytracker.com / id/1035647
Third Party AdvisoryVDB Entry
squid-cache.org / Advisories/SQUID-2016_6.txt
Vendor Advisory
ubuntu.com / usn/USN-2995-1
Third Party Advisory