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CVE-2019-12521

5.9 · MEDIUM

An issue was discovered in Squid through 4.7.

Published Apr 15, 2020CWE-193EPSS 5.91%

Overview

CVE-2019-12521 is a medium-severity vulnerability. It was published on April 15, 2020 and has a CVSS 3.1 base score of 5.9 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 5.9, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical description

An issue was discovered in Squid through 4.7. When Squid is parsing ESI, it keeps the ESI elements in ESIContext. ESIContext contains a buffer for holding a stack of ESIElements. When a new ESIElement is parsed, it is added via addStackElement. addStackElement has a check for the number of elements in this buffer, but it's off by 1, leading to a Heap Overflow of 1 element. The overflow is within the same structure so it can't affect adjacent memory blocks, and thus just leads to a crash while processing.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Reflists.opensuse.org/opensuse-security-announce/2020-05/msg00018.htmlRefwww.openwall.com/lists/oss-security/2020/04/23/1Refgitlab.com/jeriko.one/security/-/blob/master/squid/CVEs/CVE-2019-12521.txtReflists.debian.org/debian-lts-announce/2020/07/msg00009.htmlRefsecurity.gentoo.org/glsa/202005-05Refsecurity.netapp.com/advisory/ntap-20210205-0006/Refusn.ubuntu.com/4356-1/Refwww.debian.org/security/2020/dsa-4682Reflists.opensuse.org/opensuse-security-announce/2020-05/msg00018.htmlRefwww.openwall.com/lists/oss-security/2020/04/23/1

How CyberStrike helps

Frequently asked questions

What is CVE-2019-12521?

CVE-2019-12521 is a medium-severity vulnerability. It was published on April 15, 2020 and has a CVSS 3.1 base score of 5.9 (MEDIUM).

How severe is CVE-2019-12521?

This vulnerability has a CVSS 3.1 base score of 5.9, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2019-12521?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2019-12521?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2019-12521 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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