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Fencer Vulns
critical 9.8

CVE-2019-12519 json

An issue was discovered in Squid through 4.7.

published 2020-04-15 6 y ago modified 2026-06-17 4 mo ago also EUVD-2019-4114

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
6.7%
EPSS 6.7% chance of exploitation in 30 days, percentile 93%
public exploits
0
none known

Summary

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.

Patch / fix

  • squid Debian 14, Debian 13, Debian 12 4.11-1

debian advisories DEBIAN-CVE-2019-12519

  • squid Ubuntu 20.04 LTS 4.10-1ubuntu1.1
  • squid3 Ubuntu 16.04 LTS 3.5.12-1ubuntu7.11
  • squid3 Ubuntu 18.04 LTS 3.5.27-1ubuntu1.6

ubuntu advisories UBUNTU-CVE-2019-12519

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • squid RHEL 7 7:3.5.20-15.el7_8.1
  • squid-sysvinit RHEL 7 7:3.5.20-15.el7_8.1
  • squid-migration-script RHEL 7 7:3.5.20-15.el7_8.1
  • squid RHEL 8 7:4.4-8.module+el8.2.0+6449+6ba3df3e.1
  • libecap RHEL 8, RHEL 8.1 EUS 1.0.1-2.module+el8.1.0+4044+36416a77
  • squid RHEL 8.1 EUS 7:4.4-8.module+el8.1.0+6436+af881f9b.1
  • squid RHEL 8.0 E4S 7:4.4-5.module+el8.0.0+6430+d78e5241.1
  • libecap RHEL 8.0 E4S 1.0.1-2.module+el8.0.0+4045+70edde92

red hat advisories RHSA-2020:2040RHSA-2020:2041RHSA-2020:2039RHSA-2020:2038

  • squid3 SLES 11 SP4-LTSS, SLE Point of Sale 11 SP3 3.1.23-8.16.37.12.1
  • squid SLES for SAP 12 SP4, SLES for SAP 12 SP3, SLES for SAP 12 SP2 +10 more 3.5.21-26.23.1
  • squid SLES for SAP 15, SLES 15-LTSS, SLE Module for Server Applications 15 SP1 +2 more 4.11-5.17.2
  • squid SLES for SAP 12 SP5, SLES 12 SP5 4.11-4.9.1

suse advisories SUSE-SU-2020:14460-1SUSE-SU-2020:1227-1SUSE-SU-2020:1156-1SUSE-SU-2020:1134-1

  • squid openSUSE Tumbleweed 4.16-1.5
  • squid openSUSE Leap 15.1 4.11-lp151.2.15.2

opensuse advisories openSUSE-SU-2024:11403-1openSUSE-SU-2020:0623-1

  • libecap AlmaLinux 8 1.0.1-2.module_el8.6.0+2741+01592ae8

almalinux advisories ALSA-2020:2041

  • libecap Rocky Linux 8 1.0.1-2.module+el8.4.0+404+316a0dc5

rocky linux advisories RLSA-2020:2041

  • squid Alpine 3.11, Alpine 3.10, Alpine 3.9 4.11-r0

alpine advisories ALPINE-CVE-2019-12519

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • squid Arch Linux 4.12-1

arch linux advisories AVG-1146

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2019-12519 updated cvss 8.1

squid: improper check for new member in ESIExpression::Evaluate allows for stack buffer overflow

  • Red Hat Enterprise Linux 5 squid
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 6 squid, squid34
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux AppStream (v. 8) squid 4.4-8.module+el8.2.0+6449+6ba3df3e.1, libecap 1.0.1-2.module+el8.1.0+4044+36416a77
    fixed: vendor fix RHSA-2020:2041
  • Red Hat Enterprise Linux AppStream E4S (v. 8.0) squid 4.4-5.module+el8.0.0+6430+d78e5241.1, libecap 1.0.1-2.module+el8.0.0+4045+70edde92
    fixed: vendor fix RHSA-2020:2038
  • Red Hat Enterprise Linux AppStream EUS (v. 8.1) squid 4.4-8.module+el8.1.0+6436+af881f9b.1, libecap 1.0.1-2.module+el8.1.0+4044+36416a77
    fixed: vendor fix RHSA-2020:2039
  • Red Hat Enterprise Linux Server (v. 7) squid 3.5.20-15.el7_8.1, squid-migration-script 3.5.20-15.el7_8.1 Red Hat Enterprise Linux Server Optional (v. 7) squid-sysvinit 3.5.20-15.el7_8.1 Red Hat Enterprise Linux Workstation (v. 7) squid 3.5.20-15.el7_8.1, squid-migration-script 3.5.20-15.el7_8.1 Red Hat Enterprise Linux Workstation Optional (v. 7) squid-sysvinit 3.5.20-15.el7_8.1
    fixed: vendor fix RHSA-2020:2040

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

6.72% chance of exploitation in the next 30 days, higher than 93% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.