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Fencer Vulns
medium 5.5

CVE-2020-21913 json

International Components for Unicode (ICU-20850) v66.1 was discovered to contain a use after free bug in the pkg_createWithAssemblyCode fun…

published 2021-09-20 5 y ago modified 2026-10-14 26 d ago also EUVD-2020-14679

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.2%
EPSS 1.2% chance of exploitation in 30 days, percentile 68%
public exploits
0
none known

Summary

International Components for Unicode (ICU-20850) v66.1 was discovered to contain a use after free bug in the pkg_createWithAssemblyCode function in the file tools/pkgdata/pkgdata.cpp.

Patch / fix

  • 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
  • icu Debian 14, Debian 13, Debian 12 67.1-2

debian advisories DEBIAN-CVE-2020-21913

  • icu Ubuntu 18.04 LTS 60.2-3ubuntu3.2
  • icu Ubuntu Pro 14.04 LTS 52.1-3ubuntu0.8+esm2
  • icu Ubuntu Pro 16.04 LTS 55.1-7ubuntu0.5+esm1

ubuntu advisories UBUNTU-CVE-2020-21913

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

  • icu SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES for SAP 15 SP3 +20 more 65.1-150200.4.15.1
  • icu73_2 SLE Module for Basesystem 15 SP5, SLE Module for Basesystem 15 SP4, SLE Micro 5.4 +22 more 73.2-150000.1.3.1
  • icu SLE Module for Package Hub 15 SP4, SLE Module for Package Hub 15 SP3, SLE Module for Basesystem 15 SP4 +6 more 65.1-150200.4.5.1
  • icu SLE Module for Legacy 15 SP4, SLE Module for Legacy 15 SP3, openSUSE Leap 15.4 +1 more 60.2-150000.3.12.1
  • icu SLES for SAP 12 SP5, SLES 12 SP5, SLE Workstation Extension 12 SP5 +1 more 52.1-8.13.1

suse advisories SUSE-SU-2025:02079-1SUSE-SU-2023:3563-3SUSE-SU-2023:3563-2SUSE-SU-2023:3563-1SUSE-SU-2022:3142-1SUSE-SU-2022:3141-1

  • icu openSUSE Tumbleweed 73.2-2.1

opensuse advisories openSUSE-SU-2024:13127-1

  • icu Alpine 3.24, Alpine 3.23, Alpine 3.22 +7 more 66.1-r0

alpine advisories ALPINE-CVE-2020-21913

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-2020-21913 updated cvss 5.5

icu: Use after free in pkg_createWithAssemblyCode function in tools/pkgdata/pkgdata.cpp

  • Red Hat build of OpenJDK 11 com.ibm.icu com.ibm.icu Red Hat Enterprise Linux 6 icu, icu4j, libicu, icu4j-eclipse, icu4j-javadoc, java-1.6.0-openjdk, +12 more Red Hat Enterprise Linux 7 icu, libicu, webkitgtk4, webkitgtk4-jsc, java-1.6.0-openjdk, java-1.7.0-openjdk, +16 more Red Hat Enterprise Linux 8 icu, npm, icu4j, libicu, nodejs, mingw32-icu, +6 more Red Hat Enterprise Linux 9 icu, npm, libicu, nodejs, nodejs-libs, nodejs-full-i18n Red Hat JBoss Fuse 6 icu4j
    +2 more products
    Red Hat OpenShift Container Platform 4 openshift4/ose-metering-hive Red Hat Software Collections rh-nodejs12-npm, rh-nodejs12-nodejs
    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 5.5

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

Exploit prediction

1.21% chance of exploitation in the next 30 days, higher than 68% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • unicode-org.atlassian.net https://unicode-org.atlassian.net/browse/ICU-20850 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:N/A:P

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 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.