CVE-2020-15811

Publication date 24 August 2020

Last updated 24 July 2024

Ubuntu priority

Cvss 3 Severity Score

An issue was discovered in Squid before 4.13 and 5.x before 5.0.4. Due to incorrect data validation, HTTP Request Splitting attacks may succeed against HTTP and HTTPS traffic. This leads to cache poisoning. This allows any client, including browser scripts, to bypass local security and poison the browser cache and any downstream caches with content from an arbitrary source. Squid uses a string search instead of parsing the Transfer-Encoding header to find chunked encoding. This allows an attacker to hide a second request inside Transfer-Encoding: it is interpreted by Squid as chunked and split out into a second request delivered upstream. Squid will then deliver two distinct responses to the client, corrupting any downstream caches.

Status

Show unmaintained releases

Package	Ubuntu Release	Status
squid	21.04 hirsute	Fixed 4.13-1ubuntu1
	20.10 groovy	Fixed 4.13-1ubuntu1
	20.04 LTS focal	Fixed 4.10-1ubuntu1.2
	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
	18.04 LTS bionic	Fixed 3.5.27-1ubuntu1.9
	16.04 LTS xenial	Fixed 3.5.12-1ubuntu7.15
	14.04 LTS trusty	Not in release

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-2020_8.patch Upstream: fd68382

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	High
Availability impact	None
Vector	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

CVE-2020-15811

Cvss 3 Severity Score

Status

Patch details

Severity score breakdown

References

Related Ubuntu Security Notices (USN)

Other references