Squid Web Proxy up to 6.3 URN heap-based overflow

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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8.7$0-$5k0.00

Summaryinfo

A vulnerability classified as critical was found in Squid Web Proxy up to 6.3. Affected by this issue is some unknown functionality of the component URN Handler. The manipulation results in heap-based overflow. This vulnerability was named CVE-2025-54574. The attack may be performed from remote. There is no available exploit. Upgrading the affected component is advised.

Detailsinfo

A vulnerability classified as critical has been found in Squid Web Proxy up to 6.3. Affected is an unknown function of the component URN Handler. The manipulation with an unknown input leads to a heap-based overflow vulnerability. CWE is classifying the issue as CWE-122. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

Squid 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 attack when processing URN due to incorrect buffer management. This has been fixed in version 6.4. To work around this issue, disable URN access permissions.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2025-54574 since 07/25/2025. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 05/20/2026).

The vulnerability scanner Nessus provides a plugin with the ID 253521 (Debian dsa-5982 : squid - security update), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.4 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch a27bf4b84da23594150c7a86a23435df0b35b988 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (253521) and CERT Bund (WID-SEC-2025-1696). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Affected

  • Debian Linux
  • Red Hat Enterprise Linux
  • Oracle Linux
  • Open Source Squid

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.8
VulDB Meta Temp Score: 8.7

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 9.8
NVD Vector: 🔍

CNA Base Score: 9.3
CNA Vector (GitHub_M): 🔍

CVSSv2info

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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Heap-based overflow
CWE: CWE-122 / CWE-119
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 253521
Nessus Name: Debian dsa-5982 : squid - security update

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: Web Proxy 6.4
Patch: a27bf4b84da23594150c7a86a23435df0b35b988

Timelineinfo

07/25/2025 🔍
08/01/2025 +7 days 🔍
08/01/2025 +0 days 🔍
05/20/2026 +292 days 🔍

Sourcesinfo

Vendor: squid-cache.org

Advisory: GHSA-w4gv-vw3f-29g3
Status: Confirmed

CVE: CVE-2025-54574 (🔍)
GCVE (CVE): GCVE-0-2025-54574
GCVE (VulDB): GCVE-100-318528
CERT Bund: WID-SEC-2025-1696 - Squid: Schwachstelle ermöglicht Codeausführung

Entryinfo

Created: 08/01/2025 22:36
Updated: 05/20/2026 14:29
Changes: 08/01/2025 22:36 (69), 08/02/2025 13:55 (7), 08/05/2025 01:18 (1), 08/22/2025 15:50 (2), 11/07/2025 15:18 (11), 05/20/2026 14:29 (1)
Complete: 🔍
Cache ID: 216::103

VulDB is the best source for vulnerability data and more expert information about this specific topic.

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