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CVE-2023-52426 Siemens CVE debrief

CVE-2023-52426 is a medium-severity vulnerability in libexpat through version 2.5.0 that permits recursive XML Entity Expansion when XML_DTD is undefined at compile time. This condition can lead to denial of service through resource exhaustion. The vulnerability was published on August 13, 2024, and affects Siemens SINEC NMS. Siemens has released a vendor fix recommending update to version 3.0 or later. The CVSS 3.1 vector indicates a local attack vector with low attack complexity, low privileges required, and high availability impact.

Vendor
Siemens
Product
SINEC NMS
CVSS
MEDIUM 5.5
CISA KEV
Not listed in stored evidence
Original CVE published
2023-12-12
Original CVE updated
2025-08-12
Advisory published
2023-12-12
Advisory updated
2025-08-12

Who should care

Organizations operating Siemens SINEC NMS in industrial environments, OT security teams managing XML parsing components, and administrators responsible for libexpat deployments in control systems infrastructure.

Technical summary

The vulnerability exists in libexpat versions through 2.5.0 when compiled without XML_DTD defined. This configuration allows recursive XML Entity Expansion, which can be exploited to cause denial of service through excessive memory or CPU consumption. The issue affects Siemens SINEC NMS, which incorporates the vulnerable library. The attack requires local access and low privileges, with no user interaction needed. The availability impact is rated high, while confidentiality and integrity impacts are none.

Defensive priority

medium

Recommended defensive actions

  • Update Siemens SINEC NMS to version 3.0 or later per vendor guidance
  • Review libexpat compilation configurations to ensure XML_DTD is defined where required
  • Monitor CISA ICS advisories for additional affected product notifications
  • Apply defense-in-depth practices for industrial control systems per CISA recommendations

Evidence notes

Vulnerability description and remediation guidance sourced from CISA CSAF advisory ICSA-24-228-06. Vendor fix confirmed by Siemens with specific version guidance. CVSS vector and scoring details provided in source advisory.

Sources and references

Verified primary and authoritative sources

  • CVE-2023-52426 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2023-52426

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2023-52426 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2023-52426

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Source item URL

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/OT/white/2024/icsa-24-228-06.json

    cisa_csaf

  • Source reference

    Unverified legacy reference

    URL: https://cert-portal.siemens.com/productcert/csaf/ssa-784301.json

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://cert-portal.siemens.com/productcert/html/ssa-784301.html

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/news-events/ics-advisories/icsa-24-228-06

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/uscert/ics/alerts/ICS-ALERT-10-301-01

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/resources-tools/resources/ics-recommended-practices

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/topics/industrial-control-systems

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://us-cert.cisa.gov/sites/default/files/recommended_practices/NCCIC_ICS-CERT_Defense_in_Depth_2016_S508C.pdf

    Reference

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.