CVE-2019-9022 Festo Didactic SE CVE debrief

Who should care

Festo Didactic SE MES PC operators, OT/industrial system maintainers, and security teams responsible for deployments that include the affected PHP DNS component or vendor-provided XAMPP/Factory Control Panel stack.

Technical summary

The flaw is a DNS parsing error in PHP 7.x before 7.1.26, 7.2.x before 7.2.14, and 7.3.x before 7.3.2. A malformed DNS response can lead dns_get_record to mis-handle lengths and invoke memcpy in a way that reads past the buffer allocated for DNS data. The affected code path is php_parserr in ext/standard/dns.c, specifically for DNS_CAA and DNS_ANY queries. The supplied CVSS vector is AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N, indicating a remotely reachable confidentiality-impacting issue with no privileges or user interaction required.

Defensive priority

High. The issue is remotely triggerable through DNS traffic, requires no authentication or user interaction, and can expose data through out-of-bounds reads. Prioritize validation and remediation for any affected MES PC systems and any PHP deployments using the vulnerable versions.

Recommended defensive actions

• Confirm whether MES PC installations use the affected PHP versions or a vendor bundle that includes them.
• Apply the vendor remediation path identified in the advisory: obtain the current Factory Control Panel release from Festo technical support, since it is described as the replacement for XAMPP on MES PCs.
• Upgrade PHP to a fixed version if the affected component is separately managed: 7.1.26+, 7.2.14+, or 7.3.2+.
• Review DNS resolution exposure for the affected systems and ensure they rely on trusted, monitored resolvers.
• Follow CISA ICS recommended practices for defense in depth and segmentation around industrial/OT assets.

Evidence notes

This debrief is based only on the supplied CSAF/CISA source item and the official links included in the corpus. The vulnerability text explicitly states a PHP dns_get_record parsing error that can cause memcpy to read beyond the DNS buffer, and ties the impact to php_parserr in ext/standard/dns.c for DNS_CAA and DNS_ANY queries. The source metadata maps the advisory to Festo Didactic SE MES PC, and the remediation field states that Factory Control Panel replaces XAMPP on MES PCs. Timing context: the CVE published date used here is 2024-02-27, while the source item also records a later 2026-01-27 CISA republication date; that republication date should not be treated as the original vulnerability date.

Sources and references

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.