Skip to content
Fencer Vulns
critical 9.8

CVE-2019-12526 in the critical feed json

An issue was discovered in Squid before 4.9.

published 2019-11-26 6 y ago modified 2026-06-17 4 mo ago also EUVD-2019-4121

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
20.3%
EPSS 20.3% chance of exploitation in 30 days, percentile 97%
public exploits
0
none known

Summary

An issue was discovered in Squid before 4.9. URN response handling in Squid suffers from a heap-based buffer overflow. When receiving data from a remote server in response to an URN request, Squid fails to ensure that the response can fit within the buffer. This leads to attacker controlled data overflowing in the heap.

Patch / fix

  • squid Debian 14, Debian 13, Debian 12 4.9-1

debian advisories DEBIAN-CVE-2019-12526

  • squid Ubuntu 20.04 LTS 4.9-2ubuntu1
  • squid3 Ubuntu 16.04 LTS 3.5.12-1ubuntu7.9
  • squid3 Ubuntu 18.04 LTS 3.5.27-1ubuntu1.4

ubuntu advisories UBUNTU-CVE-2019-12526

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 8 7:4.11-3.module+el8.3.0+7851+7808b5f9
  • libecap RHEL 8 1.0.1-2.module+el8.1.0+4044+36416a77

red hat advisories RHSA-2020:4743

  • 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 3.5.21-26.20.1
  • squid SLES for SAP 12 SP5, SLES 12 SP5 4.9-4.3.2
  • squid SLE Module for Server Applications 15 SP1, SLE Module for Server Applications 15 4.9-5.11.1

suse advisories SUSE-SU-2020:14460-1SUSE-SU-2020:0661-1SUSE-SU-2019:3067-1SUSE-SU-2019:2975-1

  • squid openSUSE Tumbleweed 4.16-1.5
  • squid openSUSE Leap 15.1 4.9-lp151.2.7.1
  • squid openSUSE Leap 15.0 4.9-lp150.13.1

opensuse advisories openSUSE-SU-2024:11403-1openSUSE-SU-2019:2541-1openSUSE-SU-2019:2540-1

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

almalinux advisories ALSA-2020:4743

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

rocky linux advisories RLSA-2020:4743

  • squid Arch Linux 4.9-1

arch linux advisories AVG-1062

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-2019-12526 updated cvss 8.1

squid: Heap overflow issue in URN processing

  • Red Hat Enterprise Linux 6 squid, squid34 Red Hat Enterprise Linux 7 squid, squid-sysvinit, squid-migration-script
    affected: workaround, no fix planned “The following mitigation is suggested by upstream: Deny urn: protocol URI being proxied to all clients: ~~~ acl URN proto URN http_access deny URN ~~~”
  • Red Hat Enterprise Linux AppStream (v. 8) squid 4.11-3.module+el8.3.0+7851+7808b5f9, libecap 1.0.1-2.module+el8.1.0+4044+36416a77
    fixed: vendor fix “The following mitigation is suggested by upstream: Deny urn: protocol URI being proxied to all clients: ~~~ acl URN proto URN http_access deny URN ~~~” RHSA-2020:4743
  • Red Hat Enterprise Linux 5 squid
    not affected: vulnerable code not present

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

20.25% chance of exploitation in the next 30 days, higher than 97% 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.