CVE-2023-46724

Description

Squid is a caching proxy for the Web. Due to an Improper Validation of Specified Index bug, Squid versions 3.3.0.1 through 5.9 and 6.0 prior to 6.4 compiled using `--with-openssl` are vulnerable to a Denial of Service attack against SSL Certificate validation. This problem allows a remote server to perform Denial of Service against Squid Proxy by initiating a TLS Handshake with a specially crafted SSL Certificate in a server certificate chain. This attack is limited to HTTPS and SSL-Bump. This bug is fixed in Squid version 6.4. In addition, patches addressing this problem for the stable releases can be found in Squid's patch archives. Those who you use a prepackaged version of Squid should refer to the package vendor for availability information on updated packages.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
squid	25.10 questing	Fixed 6.1-2ubuntu2
	25.04 plucky	Fixed 6.1-2ubuntu2
	24.10 oracular	Fixed 6.1-2ubuntu2
	24.04 LTS noble	Fixed 6.1-2ubuntu2
	23.10 mantic	Fixed 6.1-2ubuntu1.1
	23.04 lunar	Fixed 5.7-1ubuntu3.1
	22.04 LTS jammy	Fixed 5.7-0ubuntu0.22.04.2
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Ignored end of standard support
	16.04 LTS xenial	Ignored end of standard support
	14.04 LTS trusty	Ignored end of standard support
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
	22.04 LTS jammy	Not in release
	20.04 LTS focal	Not in release
	18.04 LTS bionic	Needs evaluation
	16.04 LTS xenial	Needs evaluation
	14.04 LTS trusty	Ignored end of standard support

Notes

mdeslaur

only affects builds with openssl, which is not enabled in focal and earlier

Patch details

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

Package	Patch details
squid	Upstream: b70f864 Upstream: 12b8efc Upstream: 792ef23

Severity score breakdown

Parameter	Value
Base score	8.6 · High
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Changed
Confidentiality	None
Integrity impact	None
Availability impact	High
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

References

Related Ubuntu Security Notices (USN)

USN-6500-1
Squid vulnerabilities
21 November 2023