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Vulnerability record · CVE-2019-12524 · published 15 April 2020

CVE-2019-12524: Squid-cache squid missing authentication for critical function vulnerability

Squid Cache · Squid

An issue was discovered in Squid through 4.7. When handling requests from users, Squid checks its rules to see if the request should be denied. Squid by default comes with rules to block access to the Cache Manager, which serves detailed server information meant for the maintainer. This rule is implemented via url_regex. The handler for url_regex rules URL decodes an incoming request. This allows an attacker to encode their URL to bypass the url_regex check, and gain access to the blocked resource.

9.8 CVSS 3.1 Critical EPSS 4.3% · top 9.3% CWE-306 · Missing authentication for critical function
9.8CVSS 3.1 base score, v2 7.5
4.3%EPSS exploitation probability, 30 days
NoNot in CISA KEV
3Affected product versions listed by NVD
10References
17 Jun 2026Last modified by NVD

Description

An issue was discovered in Squid through 4.7. When handling requests from users, Squid checks its rules to see if the request should be denied. Squid by default comes with rules to block access to the Cache Manager, which serves detailed server information meant for the maintainer. This rule is implemented via url_regex. The handler for url_regex rules URL decodes an incoming request. This allows an attacker to encode their URL to bypass the url_regex check, and gain access to the blocked resource.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

3 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://gitlab.com/jeriko.one/security/-/blob/master/squid/CVEs/CVE-2019-12524.txt Third Party Advisory
https://lists.debian.org/debian-lts-announce/2020/07/msg00009.html Mailing ListThird Party Advisory
https://security.netapp.com/advisory/ntap-20210205-0006/ Third Party Advisory
https://usn.ubuntu.com/4446-1/ Third Party Advisory
https://www.debian.org/security/2020/dsa-4682 Third Party Advisory
https://gitlab.com/jeriko.one/security/-/blob/master/squid/CVEs/CVE-2019-12524.txt Third Party Advisory
https://lists.debian.org/debian-lts-announce/2020/07/msg00009.html Mailing ListThird Party Advisory
https://security.netapp.com/advisory/ntap-20210205-0006/ Third Party Advisory
https://usn.ubuntu.com/4446-1/ Third Party Advisory
https://www.debian.org/security/2020/dsa-4682 Third Party Advisory

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Source: NIST National Vulnerability Database (record CVE-2019-12524), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.