Cyber Resilience

CVE-2023-46728

Memory Safety in Squid-Cache Squid ≤ 6.0.1

Memory Safety
Published
06 November 2023
Modified
03 November 2025
Patch / advisory
View advisory
CVSS Score v3.1 7.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.060 93th percentile
Risk Priority 64 floored blend · peak EPSS

Summary

CVE-2023-46728 is a high-severity NULL Pointer Dereference (CWE-476) vulnerability in Squid-Cache Squid. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Endpoint Denial of Service (T1499); ranked in the top 7% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

A10:2025 Mishandling of Exceptional Conditions

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)
CWE-476

Related Threats

MITRE ATT&CK Enterprise Techniques

T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
attack.mitre.org →
T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
attack.mitre.org →
T1489 Service Stop Impact
Adversaries may stop or disable services on a system to render those services unavailable to legitimate users.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-49286Same product: Squid-Cache Squid
CVE-2023-50269Same product: Squid-Cache Squid
CVE-2025-62168Same product: Squid-Cache Squid
CVE-2024-23638Same product: Squid-Cache Squid
CVE-2026-32748Same product: Squid-Cache Squid
CVE-2026-47729Same product: Squid-Cache Squid
CVE-2023-49285Same product: Squid-Cache Squid
CVE-2026-33515Same product: Squid-Cache Squid
CVE-2025-59362Same product: Squid-Cache Squid
CVE-2026-33526Same product: Squid-Cache Squid

Affected Assets

squid-cache
squid
≤ 6.0.1

Mitigating Controls

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices (static analysis, code review, safe coding standards) directly prevent NULL dereference bugs during development.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing can detect NULL dereference defects before release.

A.8.25 Secure development life cycle partial match
prevents

Secure SDLC mandates defensive coding practices that can prevent NULL dereferences.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify input validation and pointer-safety rules.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles encourage defensive design that avoids unsafe pointer use.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly require NULL-pointer checks and safe dereference patterns.

References