CVE-2021-28116

3.7 LOW 13% exploit odds Fix listed Memory safety

What it is

Squid through 4.14 and 5.x through 5.0.5, in some configurations, allows information disclosure because of an out-of-bounds read in WCCP protocol data. This can be leveraged as part of a chain for remote code execution as nobody.

At a glance

Exploitability: Can be exploited over the network without logging in. Limited direct impact.
Exploit odds: 12.9% chance of exploitation in the next 30 days (EPSS). Higher than most.
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2021-03-09 22:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 03:45 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 12.9% in the next 30 days (EPSS).
Severity: 3.7 LOW (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2021-03-09 22:15 UTC
Last modified: 2026-06-17 03:45 UTC
Exploit probability: 12.9% · EPSS, next 30 days
Weakness: CWE-125 · Out-of-bounds read
Record status: Modified

Affected

squid-cache Squid ≤ 4.14
squid-cache Squid ≤ 5.0.5
Fedoraproject Fedora 33
Fedoraproject Fedora 34
Debian Linux 10.0
Debian Linux 11.0

Attack profile CVSS 3.1 · 3.7

Attack vector: Network
Complexity: High
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: None
Availability: None

Raw vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

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-2021-28116.md and follow it. Check whether this project is affected by CVE-2021-28116. 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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Fix and advisories

References

NVD record · CVE.org record