CVE-2019-12519

Name: CVE-2019-12519
Creator: NVD / NIST
Published: 2020-04-15T20:15:13.473+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 6.73%

Last modified Jun 17, 2026

CVE-2019-12519 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. An issue was discovered in Squid through 4.7. When handling the tag esi:when when ESI is enabled, Squid calls ESIExpression::Evaluate. EPSS estimates a 6.73% chance of exploitation in the next 30 days.

Description

An issue was discovered in Squid through 4.7. When handling the tag esi:when when ESI is enabled, Squid calls ESIExpression::Evaluate. This function uses a fixed stack buffer to hold the expression while it's being evaluated. When processing the expression, it could either evaluate the top of the stack, or add a new member to the stack. When adding a new member, there is no check to ensure that the stack won't overflow.

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

6.73%

93.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-787

Affected Software

Vendor	Product	Versions
Squid-Cache	Squid	>= 3.0, <= 3.5.28
Squid-Cache	Squid	>= 4.0, <= 4.10
Squid-Cache	Squid	>= 5.0, <= 5.0.1
Debian	Debian Linux	9.0
Debian	Debian Linux	10.0
Canonical	Ubuntu Linux	16.04
Canonical	Ubuntu Linux	18.04
Canonical	Ubuntu Linux	19.10
Canonical	Ubuntu Linux	20.04
Opensuse	Leap	15.1

References

http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00018.htmlMailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2020/04/23/1Mailing List, Third Party Advisory
https://gitlab.com/jeriko.one/security/-/blob/master/squid/CVEs/CVE-2019-12519.txtThird Party Advisory
https://lists.debian.org/debian-lts-announce/2020/07/msg00009.htmlMailing List, Third Party Advisory
https://security.gentoo.org/glsa/202005-05Third Party Advisory
https://security.netapp.com/advisory/ntap-20210205-0006/Third Party Advisory
https://usn.ubuntu.com/4356-1/Third Party Advisory
https://www.debian.org/security/2020/dsa-4682Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-05/msg00018.htmlMailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2020/04/23/1Mailing List, Third Party Advisory
https://gitlab.com/jeriko.one/security/-/blob/master/squid/CVEs/CVE-2019-12519.txtThird Party Advisory
https://lists.debian.org/debian-lts-announce/2020/07/msg00009.htmlMailing List, Third Party Advisory
https://security.gentoo.org/glsa/202005-05Third Party Advisory
https://security.netapp.com/advisory/ntap-20210205-0006/Third Party Advisory
https://usn.ubuntu.com/4356-1/Third Party Advisory
https://www.debian.org/security/2020/dsa-4682Third Party Advisory

Timeline

Published: Apr 15, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2019-12519?

How severe is CVE-2019-12519?

CVE-2019-12519 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 6.73% probability of exploitation in the next 30 days.

How do I fix CVE-2019-12519?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2019-12519?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST