VDB-175983 · CVE-2021-28652 · Nessus 275771

Squid Web Proxy up to 4.14/5.0.5 Cache Manager API memory leak

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
3.6	$0-$5k	0.00

Summaryinfo

A vulnerability has been found in Squid Web Proxy up to 4.14/5.0.5 and classified as problematic. Impacted is an unknown function of the component Cache Manager API. Performing a manipulation results in memory leak. This vulnerability was named CVE-2021-28652. The attack may be initiated remotely. There is no available exploit. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in Squid Web Proxy up to 4.14/5.0.5 (Firewall Software). It has been classified as problematic. This affects an unknown part of the component Cache Manager API. The manipulation with an unknown input leads to a memory leak vulnerability. CWE is classifying the issue as CWE-401. The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory. This is going to have an impact on availability.

The weakness was presented 05/28/2021. It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2021-28652. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

The vulnerability scanner Nessus provides a plugin with the ID 275771 (Oracle Linux 7 : squid (ELSA-2025-19167)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 4.15 or 5.0.6 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (275771). Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

Firewall Software

Vendor

Squid

Name

Web Proxy

Version

License

open-source

Website

Vendor: http://www.squid-cache.org/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 3.7
VulDB Meta Temp Score: 3.6

VulDB Base Score: 3.7
VulDB Temp Score: 3.6
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
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💳	💳	💳	💳	💳	💳
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Memory leak
CWE: CWE-401 / CWE-404
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 275771
Nessus Name: Oracle Linux 7 : squid (ELSA-2025-19167)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: Web Proxy 4.15/5.0.6

Timelineinfo

03/17/2021 🔍
05/28/2021 +71 days 🔍
05/28/2021 +0 days 🔍
11/20/2025 +1637 days 🔍

Sourcesinfo

Vendor: squid-cache.org

Advisory: github.com
Status: Confirmed

CVE: CVE-2021-28652 (🔍)
GCVE (CVE): GCVE-0-2021-28652
GCVE (VulDB): GCVE-100-175983

Entryinfo

Created: 05/28/2021 06:47
Updated: 11/20/2025 02:14
Changes: 05/28/2021 06:47 (39), 05/30/2021 13:42 (5), 11/20/2025 02:14 (16)
Complete: 🔍
Cache ID: 216::103