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Fencer Vulns
medium 5.9

CVE-2019-12529 json

An issue was discovered in Squid 2.x through 2.7.STABLE9, 3.x through 3.5.28, and 4.x through 4.7.

published 2019-07-11 7 y ago modified 2026-06-17 4 mo ago also EUVD-2019-4124

cvss
5.9
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
7.8%
EPSS 7.8% chance of exploitation in 30 days, percentile 94%
public exploits
0
none known

Summary

An issue was discovered in Squid 2.x through 2.7.STABLE9, 3.x through 3.5.28, and 4.x through 4.7. When Squid is configured to use Basic Authentication, the Proxy-Authorization header is parsed via uudecode. uudecode determines how many bytes will be decoded by iterating over the input and checking its table. The length is then used to start decoding the string. There are no checks to ensure that the length it calculates isn't greater than the input buffer. This leads to adjacent memory being decoded as well. An attacker would not be able to retrieve the decoded data unless the Squid maintainer had configured the display of usernames on error pages.

Patch / fix

  • squid-cache squid 2.7
  • squid Debian 14, Debian 13, Debian 12 4.8-1

debian advisories DEBIAN-CVE-2019-12529

  • squid3 Ubuntu 16.04 LTS 3.5.12-1ubuntu7.8
  • squid3 Ubuntu 18.04 LTS 3.5.27-1ubuntu1.3

ubuntu advisories UBUNTU-CVE-2019-12529

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 SLE Module for Server Applications 15 SP1, SLE Module for Server Applications 15 4.9-5.11.1
  • squid SLES 12 SP4, SLES 12 SP3-BCL, SLES 12 SP2-BCL +11 more 3.5.21-26.17.1

suse advisories SUSE-SU-2020:14460-1SUSE-SU-2019:2975-1SUSE-SU-2019:2089-1SUSE-SU-2019:2089-2

  • 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 Alpine 3.10, Alpine 3.9 4.8-r0

alpine advisories ALPINE-CVE-2019-12529

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

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-2019-12529 updated cvss 4.3

squid: Out of bounds read in Proxy-Authorization header causes DoS

  • Red Hat Enterprise Linux 5 squid Red Hat Enterprise Linux 6 squid, squid34 Red Hat Enterprise Linux 7 squid, squid-sysvinit, squid-migration-script
    affected: workaround, no fix planned “Remove 'auth_param basic ...' configuration settings from squid.conf”
  • 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 “Remove 'auth_param basic ...' configuration settings from squid.conf” RHSA-2020:4743

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

7.78% chance of exploitation in the next 30 days, higher than 94% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:P/I:N/A:N

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.