CVE-2019-12521
First published: Wed Apr 15 2020(Updated: )
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.
Credit: cve@mitre.org cve@mitre.org
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Squid-Cache Squid | >=3.0<=3.5.28 | |
| Squid-Cache Squid | >=4.0<=4.7 | |
| Squid-Cache Squid | >=5.0<=5.0.1 | |
| Canonical Ubuntu Linux | =16.04 | |
| Canonical Ubuntu Linux | =18.04 | |
| Canonical Ubuntu Linux | =19.10 | |
| Canonical Ubuntu Linux | =20.04 | |
| Debian Debian Linux | =9.0 | |
| Debian Debian Linux | =10.0 | |
| openSUSE Leap | =15.1 | |
| debian/squid | 4.13-10+deb11u3 5.7-2+deb12u2 6.10-1 |
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Reference Links
- http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00018.html
- http://www.openwall.com/lists/oss-security/2020/04/23/1
- https://gitlab.com/jeriko.one/security/-/blob/master/squid/CVEs/CVE-2019-12521.txt
- https://lists.debian.org/debian-lts-announce/2020/07/msg00009.html
- https://security.gentoo.org/glsa/202005-05
- https://security.netapp.com/advisory/ntap-20210205-0006/
- https://usn.ubuntu.com/4356-1/
- https://www.debian.org/security/2020/dsa-4682
- https://launchpad.net/bugs/cve/CVE-2019-12521
- http://www.squid-cache.org/Advisories/SQUID-2019_12.txt
- http://www.squid-cache.org/Versions/v4/changesets/squid-4-fdd4123629320aa1ee4c3481bb392437c90d188d.patch
- https://security-tracker.debian.org/tracker/CVE-2019-12521
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-12521
- https://nvd.nist.gov/vuln/detail/CVE-2019-12521
- https://ubuntu.com/security/CVE-2019-12521
Frequently Asked Questions
What is CVE-2019-12521?
CVE-2019-12521 is a vulnerability discovered in Squid through 4.7 that allows remote attackers to cause a denial of service (daemon crash) or possibly execute arbitrary code.
What is the severity of CVE-2019-12521?
The severity of CVE-2019-12521 is medium, with a CVSS score of 5.9.
How does CVE-2019-12521 affect Squid?
CVE-2019-12521 affects Squid versions up to 4.7.
How can I fix CVE-2019-12521?
To fix CVE-2019-12521, it is recommended to upgrade Squid to version 4.8 or later.
Where can I find more information about CVE-2019-12521?
More information about CVE-2019-12521 can be found at the following references: [Link 1](https://gitlab.com/jeriko.one/security/-/blob/master/squid/CVEs/CVE-2019-12521.txt), [Link 2](http://www.openwall.com/lists/oss-security/2020/04/23/1), [Link 3](https://www.debian.org/security/2020/dsa-4682).
- collector/nvd-index
- agent/weakness
- agent/type
- agent/first-publish-date
- collector/launchpad-cve
- source/Launchpad
- agent/author
- collector/nvd-cve
- source/NVD
- agent/software-canonical-lookup
- agent/remedy
- agent/severity
- agent/description
- agent/references
- collector/mitre-cve
- source/MITRE
- agent/last-modified-date
- agent/tags
- agent/event
- collector/security-tracker-debian
- source/Debian
- agent/softwarecombine
- collector/usn-cve
- source/Ubuntu
- vendor/squid-cache
- canonical/squid-cache squid
- version/squid-cache squid/3.0
- version/squid-cache squid/3.5.28
- version/squid-cache squid/4.0
- version/squid-cache squid/4.7
- version/squid-cache squid/5.0
- version/squid-cache squid/5.0.1
- vendor/canonical
- canonical/canonical ubuntu linux
- version/canonical ubuntu linux/16.04
- version/canonical ubuntu linux/18.04
- version/canonical ubuntu linux/19.10
- version/canonical ubuntu linux/20.04
- vendor/debian
- canonical/debian debian linux
- version/debian debian linux/9.0
- version/debian debian linux/10.0
- vendor/opensuse
- canonical/opensuse leap
- version/opensuse leap/15.1
- package-manager/debian