CVE-2023-42346 — Alkacon OpenCms before 16 allows XXE when the <!DOCTYPE> refers to an external h

Alkacon OpenCms before 16 allows XXE when the <!DOCTYPE> refers to an external host.

01What is this vulnerability?

Alkacon OpenCms before 16 allows XXE when the <!DOCTYPE> refers to an external host.

02Affected products

No structured affected-product list available — see references below for vendor advisories.

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2026-05-08T05:16:09.850
• Last modified: 2026-05-11T20:20:58.467

09References

• labs.watchtowr.com — https://labs.watchtowr.com/xxe-you-can-depend-on-me-opencms/