#VU65362 Input validation error in Squid - CVE-2021-33620

Vulnerability identifier: #VU65362

Vulnerability risk: Medium

CVSSv4.0: 4.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-33620

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Squid
Server applications / IDS/IPS systems, Firewalls and proxy servers

Vendor: Squid-cache.org

Description

The vulnerability allows a remote server to perform a denial of service (DoS) attack.

The vulnerability can be triggered by a header that can be expected to exist in HTTP traffic without any malicious intent by the server. A remote server can trigger the vulnerability and perform a denial of service (DoS) attack.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Squid: 4.0 - 4.14, 5.0.1 - 5.0.5

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External links
https://github.com/squid-cache/squid/security/advisories/GHSA-572g-rvwr-6c7f
https://www.squid-cache.org/Versions/v4/changesets/squid-4-1e05a85bd28c22c9ca5d3ac9f5e86d6269ec0a8c.patch
https://www.squid-cache.org/Versions/v5/changesets/squid-5-8af775ed98bfd610f9ce762fe177e01b2675588c.patch
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/T4EPIWUZDJAXADDHVOPKRBTQHPBR6H66/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LSQ3U54ZCNXR44QRPW3AV2VCS6K3TKCF/
https://lists.debian.org/debian-lts-announce/2021/06/msg00014.html

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.