CVE-2021-28652

What it is

An issue was discovered in Squid before 4.15 and 5.x before 5.0.6. Due to incorrect parser validation, it allows a Denial of Service attack against the Cache Manager API. This allows a trusted client to trigger memory leaks that. over time, lead to a Denial of Service via an unspecified short query string. This attack is limited to clients with Cache Manager API access privilege.

At a glance

Exploitability

Can be exploited over the network with an admin-level account. High risk of service disruption.

Exploit odds

4.3% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2021-05-27 12:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 03:46 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 4.3% in the next 30 days (EPSS).
• Severity: 4.9 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2021-05-27 12:15 UTC

Last modified

2026-06-17 03:46 UTC

Exploit probability

4.3% · EPSS, next 30 days

Weakness

CWE-401

Record status

Modified

Affected

• squid-cache Squid < 4.15
• squid-cache Squid < 5.0.6
• Debian Linux 9.0
• Debian Linux 10.0
• Fedoraproject Fedora 33
• Fedoraproject Fedora 34

Attack profile CVSS 3.1 · 4.9

Attack vector

Network

Complexity

Low

Privileges needed

High

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-28652.md and follow it. Check whether this project is affected by CVE-2021-28652. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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