Vulnerability record · CVE-2018-1172 · published 16 May 2018

CVE-2018-1172: Squid-cache squid null pointer dereference vulnerability

Squid Cache · Squid

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.

5.9 CVSS 3.0 Medium EPSS 8.3% · top 5.3% CWE-476 · NULL pointer dereference

5.9CVSS 3.0 base score, v2 4.3

8.3%EPSS exploitation probability, 30 days

NoNot in CISA KEV

1Affected product versions listed by NVD

4References

17 Jun 2026Last modified by NVD

Description

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

Squid Squid Cache

References

Link	Tags
http://www.squid-cache.org/Advisories/SQUID-2018_3.txt	Vendor Advisory
https://zerodayinitiative.com/advisories/ZDI-18-309	Third Party AdvisoryVDB Entry
http://www.squid-cache.org/Advisories/SQUID-2018_3.txt	Vendor Advisory
https://zerodayinitiative.com/advisories/ZDI-18-309	Third Party AdvisoryVDB Entry

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Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2018-1172), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.