Bug 1827570 (CVE-2019-12524) - CVE-2019-12524 squid: Improper access restriction in url_regex may lead to security bypass
Summary: CVE-2019-12524 squid: Improper access restriction in url_regex may lead to se...
Alias: CVE-2019-12524
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
Depends On: 1828371 1828375
Blocks: 1827553
TreeView+ depends on / blocked
Reported: 2020-04-24 08:45 UTC by Marian Rehak
Modified: 2021-06-15 19:01 UTC (History)
6 users (show)

Fixed In Version: squid 4.8
Doc Type: If docs needed, set a value
Doc Text:
A flaw was found in squid. The Cache Manager for Squid has rules that, by default, block access to anyone other than the maintainer. An attacker, with the ability to send a properly crafted URL, can bypass the url_regex check and gain access to the blocked resource. The highest threat from this vulnerability is to data confidentiality.
Clone Of:
Last Closed: 2020-11-04 02:25:07 UTC

Attachments (Terms of Use)

System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2020:4743 0 None None None 2020-11-04 03:32:03 UTC

Description Marian Rehak 2020-04-24 08:45:33 UTC
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.

Comment 3 Stefan Cornelius 2020-04-24 13:50:47 UTC
External References:


Comment 6 Product Security DevOps Team 2020-11-04 02:25:07 UTC
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):


Comment 7 errata-xmlrpc 2020-11-04 03:32:02 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2020:4743 https://access.redhat.com/errata/RHSA-2020:4743

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