Heap Buffer Overflow in Squid Caching Proxy by Squid Software
CVE-2025-54574
Key Information:
- Vendor
Squid-cache
- Status
- Vendor
- CVE Published:
- 1 August 2025
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What is CVE-2025-54574?
CVE-2025-54574 is a critical vulnerability found in Squid, an open-source caching proxy commonly used to optimize web traffic and improve access speed for clients. Specifically, this flaw exists in versions 6.3 and earlier and results from a heap buffer overflow that occurs during the processing of Uniform Resource Names (URNs) due to improper buffer management. The vulnerability could enable an attacker to execute arbitrary code remotely, potentially compromising the integrity of the Squid caching proxy and the sensitive data transmitted through it. Organizations using affected versions of Squid could face severe operational disruptions, data breaches, and malicious activities if this vulnerability is exploited.
Potential impact of CVE-2025-54574
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Remote Code Execution Risk: The heap buffer overflow may allow attackers to execute malicious code on affected systems, providing them with the ability to manipulate, steal, or destroy critical data.
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Data Integrity Compromise: Exploitation of this vulnerability could lead to unauthorized access to sensitive data that is cached or proxied through Squid, resulting in potential data leaks and regulatory compliance issues.
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Operational Disruptions: Organizations relying on Squid for web caching may experience significant service disruptions, leading to degraded performance or complete unavailability of web services, which could affect user experience and productivity.
Affected Version(s)
squid < 6.4
Exploit Proof of Concept (PoC)
PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.
News Articles

Critical Squid Flaw Allows Remote Code Execution by Attackers
A severe security vulnerability in the widely-used Squid HTTP proxy has been disclosed, potentially exposing millions of systems to remote code execution attacks.
1 month ago
References
CVSS V3.1
Timeline
- π
Vulnerability started trending
- π‘
Public PoC available
- πΎ
Exploit known to exist
- π°
First article discovered by GBHackers News
Vulnerability published
Vulnerability Reserved