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PatchSiren cyber security CVE debrief

CVE-2023-25690 Festo Didactic SE CVE debrief

CVE-2023-25690 is a critical HTTP request smuggling issue in Apache HTTP Server 2.4.0 through 2.4.55 when mod_proxy is paired with certain RewriteRule or ProxyPassMatch configurations that reinsert user-controlled URL data into a proxied request-target. In the Festo Didactic MES PC advisory, the vendor points users to a fixed Factory Control Panel replacement for XAMPP and recommends moving to a patched version to reduce exposure.

Vendor
Festo Didactic SE
Product
MES PC
CVSS
HIGH 8.8
CISA KEV
Not listed in stored evidence
Original CVE published
2025-04-07
Original CVE updated
2025-04-07
Advisory published
2025-04-07
Advisory updated
2025-04-07

Who should care

Administrators and engineers responsible for Apache HTTP Server reverse proxies, especially where mod_proxy is used with RewriteRule or ProxyPassMatch. Festo Didactic MES PC operators should also care if their deployment uses the vendor’s XAMPP-based stack or has not yet moved to the fixed Factory Control Panel.

Technical summary

The advisory describes a request smuggling condition in Apache HTTP Server when mod_proxy is enabled and a non-specific pattern matches part of the user-supplied request-target, then variable substitution inserts that data back into the proxied target. The result can be request splitting/smuggling with impacts including access-control bypass in the proxy, proxying unintended URLs to origin servers, and cache poisoning. The CVSS vector is 9.8/Critical (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

Defensive priority

Immediate. Prioritize any environment running Apache HTTP Server 2.4.0-2.4.55 with mod_proxy plus rewrite or proxy-match rules that substitute user-controlled URL components, and validate any Festo MES PC deployment against the vendor-fixed replacement.

Recommended defensive actions

  • Inventory Apache HTTP Server and Festo MES PC deployments that use mod_proxy, RewriteRule, or ProxyPassMatch.
  • Upgrade Apache HTTP Server to version 2.4.56 or later where feasible.
  • For Festo MES PCs, obtain the current Factory Control Panel version from Festo support as the vendor-recommended replacement for XAMPP.
  • Review and simplify reverse-proxy rules so user-supplied request-target data is not reinserted into proxied request-targets via variable substitution.

Evidence notes

The supplied CISA CSAF advisory (ICSA-26-027-02) ties CVE-2023-25690 to Festo Didactic SE MES PC and describes the vulnerable Apache HTTP Server behavior in mod_proxy configurations. The advisory states affected Apache versions are 2.4.0 through 2.4.55 and recommends updating to at least 2.4.56. The remediation section states that Festo released Factory Control Panel as a replacement for XAMPP on MES PCs and directs customers to Festo support for the fixed version.

Sources and references

Verified primary and authoritative sources

  • CVE-2023-25690 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2023-25690

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

  • CVE-2023-25690 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2023-25690

    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.