← Vulnerability feed

Vulnerability record · CVE-2023-46728 · published 6 November 2023

CVE-2023-46728: Squid-cache squid null pointer dereference vulnerability

Squid Cache · Squid

Squid is a caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Due to a NULL pointer dereference bug Squid is vulnerable to a Denial of Service attack against Squid's Gopher gateway. The gopher protocol is always available and enabled in Squid prior to Squid 6.0.1. Responses triggering this bug are possible to be received from any gopher server, even those without malicious intent. Gopher support has been removed in Squid version 6.0.1. Users are advised to upgrade. Users unable to upgrade should reject all gopher URL requests.

7.5 CVSS 3.1 High EPSS 6.0% · top 7.0% CWE-476 · NULL pointer dereference
7.5CVSS 3.1 base score
6.0%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
11References
17 Jun 2026Last modified by NVD

Description

Squid is a caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Due to a NULL pointer dereference bug Squid is vulnerable to a Denial of Service attack against Squid's Gopher gateway. The gopher protocol is always available and enabled in Squid prior to Squid 6.0.1. Responses triggering this bug are possible to be received from any gopher server, even those without malicious intent. Gopher support has been removed in Squid version 6.0.1. Users are advised to upgrade. Users unable to upgrade should reject all gopher URL requests.

CVSS:3.1/AV:N/AC:L/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.

References

LinkTags
https://github.com/squid-cache/squid/commit/6ea12e8fb590ac6959e9356a81aa3370576568c3 Patch
https://github.com/squid-cache/squid/security/advisories/GHSA-cg5h-v6vc-w33f Vendor Advisory
https://lists.fedoraproject.org/archives/list/[email protected]/message/A5QASTMCUSUEW3UOMKHZJB3FT
https://lists.fedoraproject.org/archives/list/[email protected]/message/MEV66D3PAAY6K7TWDT3WZBLCP
https://security.netapp.com/advisory/ntap-20231214-0006/
https://github.com/squid-cache/squid/commit/6ea12e8fb590ac6959e9356a81aa3370576568c3 Patch
https://github.com/squid-cache/squid/security/advisories/GHSA-cg5h-v6vc-w33f Vendor Advisory
https://lists.debian.org/debian-lts-announce/2025/09/msg00027.html
https://lists.fedoraproject.org/archives/list/[email protected]/message/A5QASTMCUSUEW3UOMKHZJB3FT
https://lists.fedoraproject.org/archives/list/[email protected]/message/MEV66D3PAAY6K7TWDT3WZBLCP
https://security.netapp.com/advisory/ntap-20231214-0006/

Track CVE-2023-46728 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

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

9.8CVE-2025-54574Squid-cache squid heap-based buffer overflow vulnerabilitySquid is a caching proxy for the Web. In versions 6.3 and below, Squid is vulnerable to a heap buffer overflow and possible remote code execution att…EPSS 23%9.8CVE-2020-11945Squid-cache squid integer overflow vulnerabilityAn issue was discovered in Squid before 5.0.2. A remote attacker can replay a sniffed Digest Authentication nonce to gain access to resources that ar…EPSS 27%9.8CVE-2019-12519Squid-cache squid out-of-bounds write vulnerabilityAn issue was discovered in Squid through 4.7. When handling the tag esi:when when ESI is enabled, Squid calls ESIExpression::Evaluate. This function …EPSS 6.7%9.8CVE-2019-12524Squid-cache squid missing authentication for critical function vulnerabilityAn issue was discovered in Squid through 4.7. When handling requests from users, Squid checks its rules to see if the request should be denied. Squid…EPSS 4.3%9.8CVE-2019-12526Squid-cache squid out-of-bounds write vulnerabilityAn issue was discovered in Squid before 4.9. URN response handling in Squid suffers from a heap-based buffer overflow. When receiving data from a rem…EPSS 20%9.8CVE-2019-12525Squid-cache squid out-of-bounds write vulnerabilityAn issue was discovered in Squid 3.3.9 through 3.5.28 and 4.x through 4.7. When Squid is configured to use Digest authentication, it parses the heade…EPSS 24%9.2CVE-2026-33526Squid-cache squid use after free vulnerabilitySquid is a caching proxy for the Web. Prior to version 7.5, due to heap Use-After-Free, Squid is vulnerable to Denial of Service when handling ICP tr…EPSS 13%9.1CVE-2019-12523Squid-cache squid vulnerabilityAn issue was discovered in Squid before 4.9. When handling a URN request, a corresponding HTTP request is made. This HTTP request doesn't go through …EPSS 4.3%

Source: NIST National Vulnerability Database (record CVE-2023-46728), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.