BlackTreeCVE Intelligence
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Full vulnerability report · 2021
CVE-2020-21913High confidence

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

Unknown · Unknown

Official source article: Siemens SSA-398330 ↗. Check the applicable product and release in the original source.

5.5MediumCVSS 3.1
Recommended action
Patch only the product branches with a verified fix

Medium technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 5 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:Medium, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • A structured source references public exploit or proof-of-concept material.
  • EPSS is 1.21% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict local access and enforce least privilege on affected hosts.
  • Increase monitoring for the attack path and post-exploitation behaviour described in the report.

Verification

  1. Confirm that the asset runs Unknown Unknown and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: As exposure requiresRemediation target: Within 365 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Cross-source reconciliation

Remediation availability differs by product scope

Verified remediation exists for at least one product or source, but 5 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Distribution package intelligence

Release-specific package status

Alpine, Debian findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.

7 package states
Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Distribution releaseSource packageVendor stateFixed versionEvidence
Alpine v3.23v3.23 · mainicuVendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.66.1-r0Alpine Security Database ↗Source updated 3 Oct 2026
Alpine v3.22v3.22 · mainicuVendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.66.1-r0Alpine Security Database ↗Source updated 3 Oct 2026
Alpine v3.21v3.21 · mainicuVendor fix publishedAlpine records a security fix at this version. An absent entry does not mean the package is unaffected.66.1-r0Alpine Security Database ↗Source updated 3 Oct 2026
Debian trixietrixie · sourceicuVendor fix publishedDebian records a fixed source-package version for this release.67.1-2Debian Security Tracker ↗Source updated 6 Oct 2026
Debian bookwormbookworm · sourceicuVendor fix publishedDebian records a fixed source-package version for this release.67.1-2Debian Security Tracker ↗Source updated 6 Oct 2026
Debian forkyforky · sourceicuVendor fix publishedDebian records a fixed source-package version for this release.67.1-2Debian Security Tracker ↗Source updated 6 Oct 2026
Debian sidsid · sourceicuVendor fix publishedDebian records a fixed source-package version for this release.67.1-2Debian Security Tracker ↗Source updated 6 Oct 2026
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
SSA-398330 · CSAF 2.0 · revision 18 · interimSiemens ProductCERTSSA-398330: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP >= V3.1.0 and < V3.1.5
5 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0)
  • SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0)
  • SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0)
  • SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0)
  • SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0)
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.
Remediation
Update to V3.1.5 or later version
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2020-14679

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionPatch only the product branches with a verified fix

Medium technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 5 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
01

What, why and how

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.

What

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.

Why

The program can continue using memory after it has been released, producing unsafe and attacker-influenceable behaviour.

How

An attacker operating through local access may attempt exploitation without authentication after a user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

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.

Why

The program can continue using memory after it has been released, producing unsafe and attacker-influenceable behaviour.

How

An attacker operating through local access may attempt exploitation without authentication after a user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Reference recorded

A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.

Likely attack path
local access → Use After Free → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Local
Privileges required
None: unauthenticated exploitation is possible
User interaction
Required interaction required
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-416 ↗

CWE-416: Use After Free. The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UIRequiredUser interaction: Another user must perform an action for exploitation to succeed.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.
UnauthenticatedCWE-416Public exploit reference
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

BSI · German · WID-SEC-2022-1330International Components for Unicode (icu): Schwachstelle ermöglicht Denial of Service

Ein entfernter, anonymer Angreifer kann eine Schwachstelle in International Components for Unicode (icu) ausnutzen, um einen Denial of Service Angriff durchzuführen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20210922Security Bulletin 22 Sep 2021

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 22 Sep 2021, published on 22 September 2021. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2025-AVI-0671Multiples vulnérabilités dans les produits IBM

VERecord?id=CVE-2016-6293 Référence CVE CVE-2016-7415 https://www.cve.org/CVERecord?id=CVE-2016-7415 Référence CVE CVE-2017-14952 https://www.cve.org/CVERecord?id=CVE-2017-14952 Référence CVE CVE-2017-15396 https://www.cve.org/CVERecord?id=CVE-2017-15396 Référence CVE CVE-2017-15422 https://www.cve.org/CVERecord?id=CVE-2017-15422 Référence CVE CVE-2017-17484 https://www.cve.org/CVERecord?id=CVE-2017-17484 Référence CVE CVE-2017-7867 https://www.cve.org/CVERecord?id=CVE-2017-7867 Référence CVE CVE-2017-7868 https://www.cve.org/CVERecord?id=CVE-2017-7868 Référence CVE CVE-2020-10531 https://www.cve.org/CVERecord?id=CVE-2020-10531 Référence CVE CVE-2020-21913 https://www.cve.org/CVERecord?id=CVE-2020-21913 Référence CVE CVE-2020-8908 https://www.cve.org/CVERecord?id=CVE-2020-8908 Référence CVE CVE-2022-48919 https://www.cve.org/CVERecord?id=CVE-2022-48919 Référence CVE CVE-2023-2976 https://www.cve.org/CVERecord?id=CVE-2023-2976 Référence CVE CVE-2023-40403 https://www.cve.org/CVERecord?id=CVE-2023-40403 Référence CVE CVE-2024-12133 https://www.cve.org/CVERecord?id=CVE-2024-12133 Référence CVE CVE-2024-12243 https://www.cve.org/CVERecord?id=CVE-2024-12243 Référence CVE CVE-2024-12718 https://www.cve.org/CVERecord?id=CVE-2024-12718 Référence CVE CVE-2024-31141 https://www.cve.org/CVERecord?id=CVE-

Official advisory ↗
CERT-FR · French · CERTFR-2023-AVI-1015Multiples vulnérabilités dans les produits Siemens

rd?id=CVE-2020-1752 Référence CVE CVE-2020-19185 https://www.cve.org/CVERecord?id=CVE-2020-19185 Référence CVE CVE-2020-19186 https://www.cve.org/CVERecord?id=CVE-2020-19186 Référence CVE CVE-2020-19187 https://www.cve.org/CVERecord?id=CVE-2020-19187 Référence CVE CVE-2020-19188 https://www.cve.org/CVERecord?id=CVE-2020-19188 Référence CVE CVE-2020-19189 https://www.cve.org/CVERecord?id=CVE-2020-19189 Référence CVE CVE-2020-19190 https://www.cve.org/CVERecord?id=CVE-2020-19190 Référence CVE CVE-2020-19909 https://www.cve.org/CVERecord?id=CVE-2020-19909 Référence CVE CVE-2020-21047 https://www.cve.org/CVERecord?id=CVE-2020-21047 Référence CVE CVE-2020-21913 https://www.cve.org/CVERecord?id=CVE-2020-21913 Référence CVE CVE-2020-22218 https://www.cve.org/CVERecord?id=CVE-2020-22218 Référence CVE CVE-2020-24659 https://www.cve.org/CVERecord?id=CVE-2020-24659 Référence CVE CVE-2020-24977 https://www.cve.org/CVERecord?id=CVE-2020-24977 Référence CVE CVE-2020-25692 https://www.cve.org/CVERecord?id=CVE-2020-25692 Référence CVE CVE-2020-25709 https://www.cve.org/CVERecord?id=CVE-2020-25709 Référence CVE CVE-2020-25710 https://www.cve.org/CVERecord?id=CVE-2020-25710 Référence CVE CVE-2020-26116 https://www.cve.org/CVERecord?id=CVE-2020-26116 Référence CVE CVE-2020-27618 https://www.cve.org/CVERecord?id=

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2019-016652Unicode における解放済みメモリの使用に関する脆弱性

Unicode (ICU-20850) には、解放済みメモリの使用に関する脆弱性が存在します。

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Fix availability varies by product
Affected
Fixed
Update to V3.1.5 or later version
Action
Use the product-specific evidence above. Patch only products with a verified fixed release, and keep every affected or under-investigation state without a matching fix in the remediation queue.
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 20 Sept 2021 · Last source change 4 Aug 2024, 14:30 UTC · CWE-416 · Use After Free

CVE recordCVE.org · 5.1
CVSS sourceNIST NVD
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2020-14679
Product sourceVendor CSAF · Siemens ProductCERT
Remediation sourceVendor CSAF · Siemens ProductCERT
CWE sourceNIST NVD
NVD statusNVD modified after enrichment

Missing structured fields: affected product. Missing data is not evidence of low risk; review the primary advisory.

Material change intelligence

What changed after publication

View recent updates ↗
  1. Affected versionsThe structured affected or fixed version information changed.
    Before
    n/a · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
    After
    n/a · Fixed: Update to V3.1.5 or later version
    Siemens ProductCERT ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
Fixed release recorded from official guidance
ENISA EUVD · EUVD-2020-14679↗Siemens ProductCERT security advisory · Siemens SSA-398330↗Public exploit reference↗Patch or update reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2020-21913 · cve.blacktree.nl