CVE-2021-31808

Publication date 27 May 2021

Last updated 18 August 2025

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

6.5 · Medium

Score breakdown

Description

An issue was discovered in Squid before 4.15 and 5.x before 5.0.6. Due to an input-validation bug, it is vulnerable to a Denial of Service attack (against all clients using the proxy). A client sends an HTTP Range request to trigger this.

Read the notes from the security team

Status

Package Ubuntu Release Status
squid 25.10 questing
Fixed 4.13-10ubuntu1
25.04 plucky
Fixed 4.13-10ubuntu1
24.10 oracular
Fixed 4.13-10ubuntu1
24.04 LTS noble
Fixed 4.13-10ubuntu1
23.10 mantic
Fixed 4.13-10ubuntu1
23.04 lunar
Fixed 4.13-10ubuntu1
22.10 kinetic
Fixed 4.13-10ubuntu1
22.04 LTS jammy
Fixed 4.13-10ubuntu1
21.10 impish
Fixed 4.13-10ubuntu1
21.04 hirsute
Fixed 4.13-1ubuntu4.1
20.10 groovy
Fixed 4.13-1ubuntu2.2
20.04 LTS focal
Fixed 4.10-1ubuntu1.4
18.04 LTS bionic Not in release
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release
squid3 25.10 questing Not in release
25.04 plucky Not in release
24.10 oracular Not in release
24.04 LTS noble Not in release
23.10 mantic Not in release
23.04 lunar Not in release
22.10 kinetic Not in release
22.04 LTS jammy Not in release
21.10 impish Not in release
21.04 hirsute Not in release
20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic
Fixed 3.5.27-1ubuntu1.11
16.04 LTS xenial
Vulnerable
14.04 LTS trusty Not in release

Notes

mdeslaur

same commit as CVE-2021-31806

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
squid

Severity score breakdown

Parameter Value
Base score 6.5 · Medium
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction None
Scope Unchanged
Confidentiality None
Integrity impact None
Availability impact High
Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

References

Related Ubuntu Security Notices (USN)

Other references