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Fencer Vulns
medium 5.9

CVE-2018-1172 json

This vulnerability allows remote attackers to deny service on vulnerable installations of The Squid Software Foundation Squid 3.5.27-201803…

published 2018-05-16 8 y ago modified 2026-06-17 4 mo ago also EUVD-2018-11810

cvss
5.9
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
8.2%
EPSS 8.2% chance of exploitation in 30 days, percentile 94%
public exploits
0
none known

Summary

This vulnerability allows remote attackers to deny service on vulnerable installations of The Squid Software Foundation Squid 3.5.27-20180318. Authentication is not required to exploit this vulnerability. The specific flaw exists within ClientRequestContext::sslBumpAccessCheck(). A crafted request can trigger the dereference of a null pointer. An attacker can leverage this vulnerability to create a denial-of-service condition to users of the system. Was ZDI-CAN-6088.

Patch / fix

  • squid Debian 14, Debian 13, Debian 12 4.1-1

debian advisories DEBIAN-CVE-2018-1172

  • squid3 SLES for SAP 11 SP4, SLES 11 SP4 3.1.23-8.16.37.6.1
  • squid SLES for SAP 12 SP3, SLES 12 SP3 3.5.21-26.9.1

suse advisories SUSE-SU-2018:1365-1SUSE-SU-2018:1122-1

  • squid openSUSE Tumbleweed 4.16-1.5

opensuse advisories openSUSE-SU-2024:11403-1

  • squid Alpine 3.24, Alpine 3.23, Alpine 3.22 +14 more 3.5.27-r2

alpine advisories ALPINE-CVE-2018-1172

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2018-1172 updated cvss 5.9

squid: Incorrect pointer handling when processing ESI responses allows denial of service

  • Red Hat Enterprise Linux 6 squid, squid34
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux 7 squid, squid-sysvinit, squid-migration-script
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux 5 squid Red Hat Enterprise Linux 8 squid, libecap
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

8.16% chance of exploitation in the next 30 days, higher than 94% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.0 5.9 CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:N/A:P

Affected products

  • The Squid Software Foundation The Squid Software Foundation Squid

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.