CVE-2019-12521

MEDIUM

Squid 3.0-4.7 - Denial of Service via ESI Element Stack Overflow

Title source: llm
STIX 2.1

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.

References (8)

Core 8
Core References
Mailing List, Patch, Third Party Advisory mailing-list x_refsource_mlist
http://www.openwall.com/lists/oss-security/2020/04/23/1
Third Party Advisory vendor-advisory x_refsource_debian
https://www.debian.org/security/2020/dsa-4682
Mailing List, Third Party Advisory vendor-advisory x_refsource_suse
http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00018.html
Third Party Advisory vendor-advisory x_refsource_gentoo
https://security.gentoo.org/glsa/202005-05
Third Party Advisory vendor-advisory x_refsource_ubuntu
https://usn.ubuntu.com/4356-1/
Mailing List, Third Party Advisory mailing-list x_refsource_mlist
https://lists.debian.org/debian-lts-announce/2020/07/msg00009.html
Third Party Advisory x_refsource_confirm
https://security.netapp.com/advisory/ntap-20210205-0006/

Scores

CVSS v3 5.9
EPSS 0.0576
EPSS Percentile 92.1%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Details

CWE
CWE-193 CWE-787
Status published
Products (8)
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
squid-cache/squid 3.0 - 3.5.28
Published Apr 15, 2020
Tracked Since Feb 18, 2026