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Fencer Intel
critical 9.8

CVE-2020-26154 json

url.cpp in libproxy through 0.4.15 is prone to a buffer overflow when PAC is enabled, as demonstrated by a large PAC file that is delivered…

published 6y ago modified 4mo ago also EUVD-2020-18780

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.6%
EPSS 3.6% chance of exploitation in 30 days, percentile 89%
public exploits
0
none known

Summary

url.cpp in libproxy through 0.4.15 is prone to a buffer overflow when PAC is enabled, as demonstrated by a large PAC file that is delivered without a Content-length header.

Patch / fix

  • libproxy Debian 14, Debian 13, Debian 12 0.4.15-15

debian advisories DEBIAN-CVE-2020-26154

  • libproxy Ubuntu 16.04 LTS 0.4.11-5ubuntu1.2
  • libproxy Ubuntu 18.04 LTS 0.4.15-1ubuntu0.2
  • libproxy Ubuntu 20.04 LTS 0.4.15-10ubuntu1.2

ubuntu advisories UBUNTU-CVE-2020-26154

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

  • libproxy RHEL 8 0.4.15-5.5.el8_10
  • libproxy-bin RHEL 8 0.4.15-5.5.el8_10
  • libproxy-gnome RHEL 8 0.4.15-5.5.el8_10
  • python3-libproxy RHEL 8 0.4.15-5.5.el8_10
  • libproxy-webkitgtk4 RHEL 8 0.4.15-5.5.el8_10
  • libproxy-networkmanager RHEL 8 0.4.15-5.5.el8_10
  • libproxy RHEL 8.8 EUS 0.4.15-5.4.el8_8
  • libproxy-bin RHEL 8.8 EUS 0.4.15-5.4.el8_8

red hat advisories RHEA-2024:8852RHSA-2024:6205

  • libproxy SLES for SAP 15, SLES 15-LTSS, SLE Module for Basesystem 15 SP2 +3 more 0.4.15-4.3.1
  • libproxy-plugins SLES for SAP 15, SLES 15-LTSS, SLE Workstation Extension 15 SP2 +5 more 0.4.15-4.3.1
  • libproxy SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +15 more 0.4.13-18.3.1
  • libproxy-plugins SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +15 more 0.4.13-18.3.1

suse advisories SUSE-SU-2020:2901-1SUSE-SU-2020:2900-1

  • libproxy openSUSE Tumbleweed 0.4.17-2.2
  • libproxy openSUSE Leap 15.2 0.4.15-lp152.5.3.1
  • libproxy-plugins openSUSE Leap 15.2 0.4.15-lp152.5.3.1
  • libproxy openSUSE Leap 15.1 0.4.15-lp151.4.3.1
  • libproxy-plugins openSUSE Leap 15.1 0.4.15-lp151.4.3.1

opensuse advisories openSUSE-SU-2024:10973-1openSUSE-SU-2020:1680-1openSUSE-SU-2020:1676-1

  • libproxy Alpine 3.12 0.4.15-r8
  • libproxy Alpine 3.24, Alpine 3.23, Alpine 3.22 +9 more 0.4.15-r9

alpine advisories ALPINE-CVE-2020-26154

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

  • libproxy CBL-Mariner 2.0 0.4.17-5

azure linux advisories AZL-7271

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Is CVE-2020-26154 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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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-2020-26154 updated cvss 7.5

libproxy: sending more than 102400 bytes in PAC without a Content-Length present could result in buffer overflow

  • Red Hat CodeReady Linux Builder EUS (v.8.8) libproxy-devel 0.4.15-5.4.el8_8, libproxy-debuginfo 0.4.15-5.4.el8_8, libproxy-debugsource 0.4.15-5.4.el8_8, libproxy-bin-debuginfo 0.4.15-5.4.el8_8, libproxy-gnome-debuginfo 0.4.15-5.4.el8_8, libproxy-webkitgtk4-debuginfo 0.4.15-5.4.el8_8, +1 more
    fixed: vendor fix RHSA-2024:6205
  • Red Hat Enterprise Linux AppStream (v. 8) libproxy-bin 0.4.15-5.5.el8_10, libproxy-gnome 0.4.15-5.5.el8_10, libproxy-webkitgtk4 0.4.15-5.5.el8_10, libproxy-networkmanager 0.4.15-5.5.el8_10
    fixed: vendor fix RHEA-2024:8852
  • Red Hat Enterprise Linux AppStream EUS (v.8.8) libproxy-bin 0.4.15-5.4.el8_8, libproxy-gnome 0.4.15-5.4.el8_8, libproxy-webkitgtk4 0.4.15-5.4.el8_8, libproxy-networkmanager 0.4.15-5.4.el8_8
    fixed: vendor fix RHSA-2024:6205
  • Red Hat Enterprise Linux BaseOS (v. 8) libproxy 0.4.15-5.5.el8_10, python3-libproxy 0.4.15-5.5.el8_10
    fixed: vendor fix RHEA-2024:8852
  • Red Hat Enterprise Linux BaseOS EUS (v.8.8) libproxy 0.4.15-5.4.el8_8, python3-libproxy 0.4.15-5.4.el8_8
    fixed: vendor fix RHSA-2024:6205
  • Red Hat Enterprise Linux CRB (v. 8) libproxy-devel 0.4.15-5.5.el8_10, libproxy-debuginfo 0.4.15-5.5.el8_10, libproxy-debugsource 0.4.15-5.5.el8_10, libproxy-bin-debuginfo 0.4.15-5.5.el8_10, libproxy-gnome-debuginfo 0.4.15-5.5.el8_10, libproxy-webkitgtk4-debuginfo 0.4.15-5.5.el8_10, +1 more
    fixed: vendor fix RHEA-2024:8852
  • Red Hat Enterprise Linux 6 libproxy, libproxy-bin, libproxy-kde, libproxy-gnome, libproxy-mozjs, libproxy-python, +1 more Red Hat Enterprise Linux 7 libproxy, libproxy-bin, libproxy-kde, libproxy-gnome, libproxy-mozjs, libproxy-python, +2 more
    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

3.56% chance of exploitation in the next 30 days, higher than 89% of all scored CVEs (FIRST EPSS, 2026-11-09).

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 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P

Classification

Weakness
  • CWE-120 Buffer Copy without Checking Size of Input

References

Sources

Fencer Intel 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.