CVE-2019-18676

Publication date 26 November 2019

Last updated 25 August 2025

Ubuntu priority

Cvss 3 Severity Score

Description

An issue was discovered in Squid 3.x and 4.x through 4.8. Due to incorrect input validation, there is a heap-based buffer overflow that can result in Denial of Service to all clients using the proxy. Severity is high due to this vulnerability occurring before normal security checks; any remote client that can reach the proxy port can trivially perform the attack via a crafted URI scheme.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
squid	21.04 hirsute	Fixed 4.9-2ubuntu1
	20.10 groovy	Fixed 4.9-2ubuntu1
	20.04 LTS focal	Fixed 4.9-2ubuntu1
	19.10 eoan	Fixed 4.8-1ubuntu2.1
	19.04 disco	Fixed 4.4-1ubuntu2.3
	18.04 LTS bionic	Not in release
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release
squid3	21.04 hirsute	Not in release
	20.10 groovy	Not in release
	20.04 LTS focal	Not in release
	19.10 eoan	Not in release
	19.04 disco	Not in release
	18.04 LTS bionic	Fixed 3.5.27-1ubuntu1.7
	16.04 LTS xenial	Fixed 3.5.12-1ubuntu7.12
	14.04 LTS trusty	Not in release

Notes

mdeslaur

same fix as CVE-2019-12523 This was fixed in 4.x by rewriting the URI parser to use SBuf. fixed in Debian's 3.5.23-5+deb9u2

Patch details

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

Package	Patch details
squid	Upstream: http://www.squid-cache.org/Versions/v4/changesets/squid-4-fbbdf75efd7a5cc244b4886a9d42ea458c5a3a73.patch

Severity score breakdown

Parameter	Value
Base score	7.5 · High
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	None
Integrity impact	None
Availability impact	High
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H