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CVE-2016-4053

24
FAUCET Score

CVE-2016-4053 affects Squid 3.x before 3.5.17 and 4.x before 4.0.9, allowing remote attackers to obtain sensitive stack layout information via crafted Edge Side Includes (ESI) responses due to incorrect assert usage and compiler optimization. This vulnerability carries a CVSSv3 score of 3.7 (Low), indicating a network-based attack with high complexity, leading to a low impact on confidentiality. While it is on a "Hot List," there is no evidence of active exploitation in the wild (KEV: No), and no public exploit code is available on platforms like Metasploit or ExploitDB. Community discussion shows some awareness, with references to a NASL script and a markdown file on GitHub, but its EPSS score of 0.262030000 suggests a low probability of exploitation.

Impacted Technologies

VendorProductVersion(s)CPE
3.0CPE matchmatch criteria
cpe:2.3:a:squid-cache:squid:3.0:*:*:*:*:*:*:*
3.1CPE matchmatch criteria
cpe:2.3:a:squid-cache:squid:3.1:*:*:*:*:*:*:*
3.1.0.1CPE matchmatch criteria
cpe:2.3:a:squid-cache:squid:3.1.0.1:*:*:*:*:*:*:*
3.1.0.2CPE matchmatch criteria
cpe:2.3:a:squid-cache:squid:3.1.0.2:*:*:*:*:*:*:*
3.1.0.3CPE matchmatch criteria
cpe:2.3:a:squid-cache:squid:3.1.0.3:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

3.7LOW

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

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
LOW
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
2.2
Impact Score
1.4
CvssVersion
3.0

Exploit Intelligence

EPSS Score
14.36%
Probability of exploitation in next 30 days
EPSS Percentile
96.2%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
This CVE's current EPSS score of 0.1436 is in the 97th percentile among its peer group of 1,506 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.3 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 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-2016-4053Moderate

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
Third Party Advisory
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