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Fencer Intel
medium 6.5

CVE-2020-24977 json

GNOME project libxml2 v2.9.10 has a global buffer over-read vulnerability in...

published 6y ago modified 26d ago also EUVD-2020-17677 , JLSEC-2025-69

cvss
6.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.0%
EPSS 3.0% chance of exploitation in 30 days, percentile 87%
public exploits
0
none known

Summary

GNOME project libxml2 v2.9.10 has a global buffer over-read vulnerability in xmlEncodeEntitiesInternal at libxml2/entities.c. The issue has been fixed in commit 50f06b3e.

Patch / fix

  • julia XML2_jll 2.9.12+0
  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.5
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP V3.1.5
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP V3.1.5
  • libxml2 Debian 14, Debian 13, Debian 12 2.9.10+dfsg-6.2

debian advisories DEBIAN-CVE-2020-24977

  • libxml2 Ubuntu 18.04 LTS 2.9.4+dfsg1-6.1ubuntu1.4
  • libxml2 Ubuntu 20.04 LTS 2.9.10+dfsg-5ubuntu0.20.04.1
  • libxml2 Ubuntu Pro 14.04 LTS 2.9.1+dfsg1-3ubuntu4.13+esm2
  • libxml2 Ubuntu Pro 16.04 LTS 2.9.3+dfsg1-1ubuntu0.7+esm1

ubuntu advisories UBUNTU-CVE-2020-24977

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

  • libxml2 RHEL 8 2.9.7-9.el8
  • python3-libxml2 RHEL 8 2.9.7-9.el8

red hat advisories RHSA-2021:1597

  • libxml2 SLES 11 SP4-LTSS, SLE Point of Sale 11 SP3 2.7.6-0.77.36.1
  • libxml2-python SLES 11 SP4-LTSS, SLE Point of Sale 11 SP3 2.7.6-0.77.36.1
  • libxml2 SLE Module for Basesystem 15 SP2, SLE Module for Basesystem 15 SP1 2.9.7-3.25.1
  • python-libxml2-python SLE Module for Python 2 15 SP2, SLE Module for Python 2 15 SP1, SLE Module for Basesystem 15 SP2 +1 more 2.9.7-3.25.1
  • libxml2 SLES for SAP 12 SP5, SLES 12 SP5, SLE Software Development Kit 12 SP5 2.9.4-46.34.1
  • python-libxml2 SLES for SAP 12 SP5, SLES 12 SP5 2.9.4-46.34.1

suse advisories SUSE-SU-2021:14729-1SUSE-SU-2020:2612-1SUSE-SU-2020:2609-1

  • rubygem-nokogiri openSUSE Tumbleweed 1.18.9-1.4
  • rubygem-nokogiri openSUSE Tumbleweed 1.18.2-1.1
  • rubygem-nokogiri openSUSE Tumbleweed 1.15.5-1.5
  • libxml2 openSUSE Tumbleweed 2.9.12-1.2
  • rubygem-nokogiri openSUSE Tumbleweed 1.13.3-1.1
  • ruby3.2-rubygem-nokogiri openSUSE Tumbleweed 1.13.9-1.7
  • libxml2 openSUSE Leap 15.2 2.9.7-lp152.10.3.1
  • python-libxml2-python openSUSE Leap 15.2 2.9.7-lp152.10.3.1

opensuse advisories openSUSE-SU-2026:10356-1openSUSE-SU-2025:14697-1openSUSE-SU-2024:14174-1openSUSE-SU-2024:11016-1openSUSE-SU-2024:11912-1openSUSE-SU-2024:13165-1

  • libxml2 Rocky Linux 8 2.9.7-9.el8

rocky linux advisories RLSA-2021:1597

  • libxml2 Alpine 3.10 2.9.9-r4
  • libxml2 Alpine 3.11 2.9.10-r4
  • libxml2 Alpine 3.24, Alpine 3.23, Alpine 3.22 +10 more 2.9.10-r5
  • libxml2 Alpine 3.9 2.9.9-r3

alpine advisories ALPINE-CVE-2020-24977

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

  • libxml2 Arch Linux 2.9.10-6

arch linux advisories AVG-1263

Is CVE-2020-24977 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

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-2020-24977 updated cvss 6.5

libxml2: Buffer overflow vulnerability in xmlEncodeEntitiesInternal() in entities.c

  • Red Hat Enterprise Linux 5 libxml2 Red Hat Enterprise Linux 6 libxml2, libxml2-python
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 7 libxml2, libxml2-python
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Enterprise Linux AppStream (v. 8) libxml2-devel 2.9.7-9.el8, libxml2-debuginfo 2.9.7-9.el8, libxml2-debugsource 2.9.7-9.el8, python3-libxml2-debuginfo 2.9.7-9.el8 Red Hat Enterprise Linux BaseOS (v. 8) libxml2 2.9.7-9.el8, python3-libxml2 2.9.7-9.el8
    fixed: vendor fix RHSA-2021:1597
  • Red Hat JBoss Core Services libxml2
    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

cisa ICSA-23-348-10 updated cvss 6.5

Siemens SIMATIC S7-1500

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) >= 3.1.0, < 3.1.5 Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= 3.1.0, < 3.1.5
    affected: fixed in V3.1.5, mitigation support.industry.siemens.com

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

cisa ICSA-21-336-06 updated cvss 6.5

Hitachi Energy APM Edge

  • Hitachi Energy APM Edge 3.0, 2.0, 1.0
    affected: vendor fix, mitigation “Physically protect process control systems from direct access by unauthorized personnel.” search.abb.com

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

cisa ICSA-21-336-08 updated cvss 6.5

Hitachi Energy RTU500 series

  • Hitachi Energy RTU500 series CMU Firmware 12.2.*, 13.1.*, 13.0.*, 12.0.*
    affected: vendor fix, mitigation “Physically protect process control systems from direct access by unauthorized personnel.” search.abb.com

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

Exploit prediction

2.98% chance of exploitation in the next 30 days, higher than 87% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • gitlab.gnome.org https://gitlab.gnome.org/GNOME/libxml2/-/issues/178 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
NVD 2.0 6.4 AV:N/AC:L/Au:N/C:P/I:N/A:P
OSV 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L

Affected packages

ecosystem package affected fixed in
julia XML2_jll
>=2.9.10+0, <2.9.12+0
2.9.12+0

Affected products

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP

Classification

Weakness

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.