Cyber Resilience

CVE-2023-49285

Memory Safety in Squid-Cache Squid ≤ 6.4

High EPSSMemory Safety
Published
04 December 2023
Modified
21 November 2024
Patch / advisory
CVSS Score v3.1 8.6
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
EPSS Score 0.89 99.8th percentile
Risk Priority 88 floored blend · peak EPSS

Summary

CVE-2023-49285 is a high-severity Buffer Over-read (CWE-126) vulnerability in Squid-Cache Squid. Its CVSS base score is 8.6 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique OS Credential Dumping (T1003); ranked in the top 0.2% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

Squid, a widely used caching proxy supporting HTTP, HTTPS, FTP and related protocols, contains a buffer overread vulnerability in its HTTP message processing code. The flaw, tracked as CVE-2023-49285 and assigned CWE-126 and CWE-125, allows an attacker to trigger a denial of service by supplying specially crafted input that causes Squid to read beyond allocated buffer boundaries. The issue affects multiple maintained release lines prior to the 6.5 release and carries a CVSS 3.1 base score of 8.6 reflecting network attack vector, low complexity, and high availability impact with no required privileges or user interaction.

An unauthenticated remote attacker can send malicious HTTP messages directly to an exposed Squid instance, causing the proxy to crash or become unresponsive. Because the vulnerability resides in core message parsing, the attack can be mounted against any deployment that accepts untrusted client or server traffic, including forward and reverse proxy configurations.

Official advisories and patches published by the Squid project state that the bug is resolved in version 6.5 and provide back-ported fixes for the 5.x series via the referenced SQUID-2023_7 patches and corresponding Git commits. No workarounds are documented, and administrators are advised to upgrade immediately. The associated EPSS score has remained low and stable near 0.096, indicating limited observed exploitation interest to date.

EU & UK References

Vulnerability Data

Squid is a caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Due to a Buffer Overread bug Squid is vulnerable to a Denial of Service attack against Squid HTTP Message processing. This bug is fixed by Squid…

more

version 6.5. Users are advised to upgrade. There are no known workarounds for this vulnerability.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1003 OS Credential Dumping Credential Access
Adversaries may attempt to dump credentials to obtain account login and credential material, normally in the form of a hash or a clear text password.
T1005 Data from Local System Collection
Adversaries may search local system sources, such as file systems, configuration files, local databases, virtual machine files, or process memory, to find files of interest and sensitive data prior to Exfiltration.
T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-47729Same product: Squid-Cache Squid
CVE-2026-33515Same product: Squid-Cache Squid
CVE-2024-37894Same product: Squid-Cache Squid
CVE-2025-54574Same product: Squid-Cache Squid
CVE-2023-46724Same product: Squid-Cache Squid
CVE-2024-23638Same product: Squid-Cache Squid
CVE-2026-32748Same product: Squid-Cache Squid
CVE-2025-59362Same product: Squid-Cache Squid
CVE-2026-33526Same product: Squid-Cache Squid
CVE-2023-49288Same product: Squid-Cache Squid

Affected Assets

squid-cache
squid
≤ 6.4

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 development practices directly prevent introduction of buffer over-read weaknesses.

ID.RA-01 partial match
prevents

Vulnerability identification processes can discover buffer over-read flaws via scanning or review.

PR.PS-02 partial match
prevents

Patching or replacing vulnerable software removes known instances of buffer over-read bugs.

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.

finds

Security testing in development can detect buffer over-reads before release.

A.8.15 Logging partial match
finds

Logging can record evidence of an out-of-bounds read but does not prevent the weakness itself.

prevents

Secure SDLC mandates input validation and bounds checking that can prevent buffer over-reads.

prevents

Application security requirements can specify buffer-size and bounds-checking rules.

prevents

Secure architecture principles include memory-safety and bounds-checking design choices.

prevents

Secure coding standards directly require bounds-checked buffer access, mitigating over-reads.

References