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Full vulnerability report · 2021
CVE-2020-27009High confidence

Siemens APOGEE PXC Compact (BACnet) — Use of Out-of-range Pointer Offset

Siemens · APOGEE PXC Compact (BACnet)

8.1HighCVSS 3.1
Recommended action
Within 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
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.

2 current
SSA-180579 · CSAF 2.0 · revision 2 · interimSiemens ProductCERTSSA-180579: Privilege Management Vulnerability and Multiple Nucleus RTOS Vulnerabilities in APOGEE/TALON Field Panels before V3.5.5/V2.8.20
6 known affected

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

  • APOGEE PXC Compact (BACnet)
  • APOGEE PXC Compact (P2 Ethernet)
  • APOGEE PXC Modular (BACnet)
  • APOGEE PXC Modular (P2 Ethernet)
  • TALON TC Compact (BACnet)
  • TALON TC Modular (BACnet)
Summary
The DNS domain name record decompression functionality does not properly validate the pointer offset values. The parsing of malformed responses could result in a write past the end of an allocated structure. An attacker with a privileged position in the network could leverage this vulnerability to execute code in the context of the current process or cause a denial-of-service condition.
Remediation
Update to V2.8.20 or later version
SSA-185699 · CSAF 2.0 · revision 3 · finalSiemens ProductCERTSSA-185699: Out of Bounds Write Vulnerabilities (NAME:WRECK) in the DNS Module of Nucleus RTOS
2 known affected

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

  • Nucleus NET
  • Nucleus Source Code
Summary
The DNS domain name record decompression functionality does not properly validate the pointer offset values. The parsing of malformed responses could result in a write past the end of an allocated structure. An attacker with a privileged position in the network could leverage this vulnerability to execute code in the context of the current process or cause a denial-of-service condition.
Remediation
Contact customer support to receive patch and update information
Optional official sources

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

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

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-2020-19533

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 actionWithin 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

A vulnerability has been identified in APOGEE PXC Compact (BACnet) (All versions < V3.5.5), APOGEE PXC Compact (P2 Ethernet) (All versions < V2.8.20), APOGEE PXC Modular (BACnet) (All versions < V3.5.5), APOGEE PXC Modular (P2 Ethernet) (All versions < V2.8.20), Nucleus NET (All versions < V5.2), Nucleus Source Code (Versions including affected DNS modules), TALON TC Compact (BACnet) (All versions < V3.5.5), TALON TC Modular (BACnet) (All versions < V3.5.5). The DNS domain name record decompression functionality does not properly validate the pointer offset values. The parsing of malformed responses could result in a write past the end of an allocated structure. An attacker with a privileged position in the network could leverage this vulnerability to execute code in the context of the current process or cause a denial-of-service condition.

What

A vulnerability has been identified in APOGEE PXC Compact (BACnet) (All versions < V3.5.5), APOGEE PXC Compact (P2 Ethernet) (All versions < V2.8.20), APOGEE PXC Modular (BACnet) (All versions < V3.5.5), APOGEE PXC Modular (P2 Ethernet) (All versions < V2.8.20), Nucleus NET (All versions < V5.2), Nucleus Source Code (Versions including affected DNS modules), TALON TC Compact (BACnet) (All versions < V3.5.5), TALON TC Modular (BACnet) (All versions < V3.5.5). The DNS domain name record decompression functionality does not properly validate the pointer offset values. The parsing of malformed responses could result in a write past the end of an allocated structure. An attacker with a privileged position in the network could leverage this vulnerability to execute code in the context of the current process or cause a denial-of-service condition.

Why

The product performs pointer arithmetic on a valid pointer, but it uses an offset that can point outside of the intended range of valid memory locations for the resulting pointer.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may execute code or commands in the affected security context.

What

A vulnerability has been identified in APOGEE PXC Compact (BACnet) (All versions < V3.5.5), APOGEE PXC Compact (P2 Ethernet) (All versions < V2.8.20), APOGEE PXC Modular (BACnet) (All versions < V3.5.5), APOGEE PXC Modular (P2 Ethernet) (All versions < V2.8.20), Nucleus NET (All versions < V5.2), Nucleus Source Code (Versions including affected DNS modules), TALON TC Compact (BACnet) (All versions < V3.5.5), TALON TC Modular (BACnet) (All versions < V3.5.5). The DNS domain name record decompression functionality does not properly validate the pointer offset values. The parsing of malformed responses could result in a write past the end of an allocated structure. An attacker with a privileged position in the network could leverage this vulnerability to execute code in the context of the current process or cause a denial-of-service condition.

Why

The product performs pointer arithmetic on a valid pointer, but it uses an offset that can point outside of the intended range of valid memory locations for the resulting pointer.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may execute code or commands in the affected security context.

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.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Use of Out-of-range Pointer Offset → execute code or commands in the affected security context
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
High: exploitation depends on specific conditions
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-823 ↗

CWE-823: Use of Out-of-range Pointer Offset. The product performs pointer arithmetic on a valid pointer, but it uses an offset that can point outside of the intended range of valid memory locations for the resulting pointer.

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

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

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
After compromise, an attacker may use built-in shells, scripting engines, scheduled tasks and native network utilities for discovery, persistence or movement. This is a plausible LoTL path, not evidence that it has occurred for every attack.
NetworkUnauthenticatedRemote code executionCWE-823
A

Official authority intelligence

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

BSI · German · WID-SEC-W-2023-1986NAME:WRECK: Mehrere Schwachstellen in TCP/IP Stacks

Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Siemens Nucleus Net, Siemens Nucleus RTOS, Microsoft Azure RTOS NetX und Wind River VxWorks ausnutzen, um beliebigen Programmcode mit Administratorrechten auszuführen oder einen Denial of Service zu verursachen.

Official advisory
CERT-FR · French · CERTFR-2023-AVI-0633Multiples vulnérabilités dans les produits Siemens

u 8 août 2023 https://cert-portal.siemens.com/productcert/html/ssa-472630.html Bulletin de sécurité Siemens ssa-770902 du 8 août 2023 https://cert-portal.siemens.com/productcert/html/ssa-770902.html Bulletin de sécurité Siemens ssa-811403 du 8 août 2023 https://cert-portal.siemens.com/productcert/html/ssa-811403.html Bulletin de sécurité Siemens ssa-908185 du 8 août 2023 https://cert-portal.siemens.com/productcert/html/ssa-908185.html Bulletin de sécurité Siemens ssa-975961 du 8 août 2023 https://cert-portal.siemens.com/productcert/html/ssa-975961.html Référence CVE CVE-2020-15795 https://www.cve.org/CVERecord?id=CVE-2020-15795 Référence CVE CVE-2020-27009 https://www.cve.org/CVERecord?id=CVE-2020-27009 Référence CVE CVE-2020-27736 https://www.cve.org/CVERecord?id=CVE-2020-27736 Référence CVE CVE-2020-27737 https://www.cve.org/CVERecord?id=CVE-2020-27737 Référence CVE CVE-2020-27738 https://www.cve.org/CVERecord?id=CVE-2020-27738 Référence CVE CVE-2020-28388 https://www.cve.org/CVERecord?id=CVE-2020-28388 Référence CVE CVE-2021-25677 https://www.cve.org/CVERecord?id=CVE-2021-25677 Référence CVE CVE-2021-31239 https://www.cve.org/CVERecord?id=CVE-2021-31239 Référence CVE CVE-2021-41544 https://www.cve.org/CVERecord?id=CVE-2021-41544 Référence CVE CVE-2022-25634 https://www.cve.org/CVERecord?id=

Official advisory
CERT-FR · French · CERTFR-2021-AVI-854Multiples vulnérabilités dans les produits Siemens

9 du 9 novembre 2021 https://cert-portal.siemens.com/productcert/pdf/ssa-779699.pdf Bulletin de sécurité Siemens ssa-840188 du 9 novembre 2021 https://cert-portal.siemens.com/productcert/pdf/ssa-840188.pdf Bulletin de sécurité Siemens ssa-917476 du 9 novembre 2021 https://cert-portal.siemens.com/productcert/pdf/ssa-917476.pdf Référence CVE CVE-2020-10052 https://www.cve.org/CVERecord?id=CVE-2020-10052 Référence CVE CVE-2020-10053 https://www.cve.org/CVERecord?id=CVE-2020-10053 Référence CVE CVE-2020-10054 https://www.cve.org/CVERecord?id=CVE-2020-10054 Référence CVE CVE-2020-15795 https://www.cve.org/CVERecord?id=CVE-2020-15795 Référence CVE CVE-2020-27009 https://www.cve.org/CVERecord?id=CVE-2020-27009 Référence CVE CVE-2020-27736 https://www.cve.org/CVERecord?id=CVE-2020-27736 Référence CVE CVE-2020-27737 https://www.cve.org/CVERecord?id=CVE-2020-27737 Référence CVE CVE-2020-27738 https://www.cve.org/CVERecord?id=CVE-2020-27738 Référence CVE CVE-2020-28388 https://www.cve.org/CVERecord?id=CVE-2020-28388 Référence CVE CVE-2021-25663 https://www.cve.org/CVERecord?id=CVE-2021-25663 Référence CVE CVE-2021-25664 https://www.cve.org/CVERecord?id=CVE-2021-25664 Référence CVE CVE-2021-25677 https://www.cve.org/CVERecord?id=CVE-2021-25677 Référence CVE CVE-2021-27393 https://www.cve.org/CVERecord?id=

Official advisory
CERT-FR · French · CERTFR-2021-AVI-255Multiples vulnérabilités dans les produits Siemens

d?id=CVE-2019-19296 Référence CVE CVE-2019-19297 https://www.cve.org/CVERecord?id=CVE-2019-19297 Référence CVE CVE-2019-19298 https://www.cve.org/CVERecord?id=CVE-2019-19298 Référence CVE CVE-2019-19299 https://www.cve.org/CVERecord?id=CVE-2019-19299 Référence CVE CVE-2019-19956 https://www.cve.org/CVERecord?id=CVE-2019-19956 Référence CVE CVE-2020-15795 https://www.cve.org/CVERecord?id=CVE-2020-15795 Référence CVE CVE-2020-25243 https://www.cve.org/CVERecord?id=CVE-2020-25243 Référence CVE CVE-2020-25244 https://www.cve.org/CVERecord?id=CVE-2020-25244 Référence CVE CVE-2020-26997 https://www.cve.org/CVERecord?id=CVE-2020-26997 Référence CVE CVE-2020-27009 https://www.cve.org/CVERecord?id=CVE-2020-27009 Référence CVE CVE-2020-27736 https://www.cve.org/CVERecord?id=CVE-2020-27736 Référence CVE CVE-2020-27737 https://www.cve.org/CVERecord?id=CVE-2020-27737 Référence CVE CVE-2020-27738 https://www.cve.org/CVERecord?id=CVE-2020-27738 Référence CVE CVE-2020-28385 https://www.cve.org/CVERecord?id=CVE-2020-28385 Référence CVE CVE-2020-7595 https://www.cve.org/CVERecord?id=CVE-2020-7595 Référence CVE CVE-2021-25663 https://www.cve.org/CVERecord?id=CVE-2021-25663 Référence CVE CVE-2021-25664 https://www.cve.org/CVERecord?id=CVE-2021-25664 Référence CVE CVE-2021-25670 https://www.cve.org/CVERecord?id=CV

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.
Patch available
Affected
APOGEE PXC Compact (BACnet); APOGEE PXC Compact (P2 Ethernet); APOGEE PXC Modular (BACnet); APOGEE PXC Modular (P2 Ethernet); TALON TC Compact (BACnet); TALON TC Modular (BACnet)
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
Update to V2.8.20 or later version
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 22 Apr 2021 · Last source change 4 Aug 2024, 16:03 UTC · CWE-823 · Use of Out-of-range Pointer Offset

CVE recordCVE.org · 5.1
CVSS sourceCNA
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-2020-19533
Product sourceVendor CSAF · Siemens ProductCERT
Remediation sourceVendor CSAF · Siemens ProductCERT
CWE sourceCNA
NVD statusNVD modified after enrichment

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates →

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
ENISA EUVD · EUVD-2020-19533↗Vendor CSAF · Siemens ProductCERT↗CVE authority or vendor 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-2020-27009 · cve.blacktree.nl