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CVE-2021-46661 Festo Didactic SE CVE debrief

CVE-2021-46661 describes a denial-of-service condition in MariaDB through 10.5.9 that can crash query-processing paths when an unused common table expression (CTE) is present. In the Festo Didactic SE MES PC advisory context, this maps to an application crash in find_field_in_tables and find_order_in_list, so the primary risk is loss of availability rather than data exposure or code execution. The source advisory was initially published on 2024-02-27 and later republished on 2026-01-27; the remediation entry in the source points to Festo’s Factory Control Panel replacement guidance for MES PCs.

Vendor
Festo Didactic SE
Product
MES PC
CVSS
MEDIUM 5.5
CISA KEV
Not listed in stored evidence
Original CVE published
2024-02-27
Original CVE updated
2026-01-27
Advisory published
2024-02-27
Advisory updated
2026-01-27

Who should care

Operators and support teams responsible for Festo Didactic SE MES PC systems, especially environments that still rely on the affected MariaDB/XAMPP-based stack and have local engineering or administrative access paths.

Technical summary

The supplied advisory data identifies a crash in MariaDB query resolution functions find_field_in_tables and find_order_in_list triggered by an unused CTE. The CVSS vector in the source is AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H, which indicates a local, low-privilege denial-of-service issue with no confidentiality or integrity impact and high availability impact. The source corpus does not describe code execution, persistence, or remote exploitation details.

Defensive priority

Medium

Recommended defensive actions

  • Confirm whether MES PC deployments use the affected MariaDB/XAMPP-based software stack.
  • Obtain and deploy the current Factory Control Panel version from Festo technical support, as noted in the advisory remediation.
  • Restrict local database and engineering access to trusted users only, since the CVSS vector requires local privileges.
  • Test service recovery procedures so a database or application crash does not interrupt operations longer than necessary.
  • Monitor the official CISA and Festo advisory links for any follow-up guidance or revised remediation notes.

Evidence notes

Evidence comes from the CISA CSAF advisory for Festo Didactic SE MES PC and the linked official records. The source states: 'MariaDB through 10.5.9 allows an application crash in find_field_in_tables and find_order_in_list via an unused common table expression (CTE).' The remediation section says Festo Didactic has released Factory Control Panel as a replacement for XAMPP on its MES PCs and includes fixes for these vulnerabilities. The provided CVSS vector is AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

Sources and references

Verified primary and authoritative sources

  • CVE-2021-46661 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2021-46661

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

  • CVE-2021-46661 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2021-46661

    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/2026/icsa-26-027-02.json

    cisa_csaf

  • Source reference

    Unverified legacy reference

    URL: https://festo.csaf-tp.certvde.com/.well-known/csaf/white/2024/fsa-202402.json

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://certvde.com/en/advisories/vendor/festo/

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://festo.com/psirt

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://certvde.com/en/advisories/VDE-2023-065

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/news-events/ics-advisories/icsa-26-027-02

    Reference

  • Source reference

    Unverified legacy reference

    URL: https://www.cisa.gov/news-events/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

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.