CVE-2026-115457 baserproject CVE debrief

Who should care

Defenders of baserCMS installations, especially those with public commenting enabled, should assess exposure and prioritize patching or mitigating this vulnerability. This vulnerability allows an unauthenticated attacker to inject malicious shortcodes into blog comments, potentially compromising the authenticated browser context of administrators and allowing execution of arbitrary JavaScript on the site's origin.

Why it matters

This vulnerability allows an unauthenticated attacker to inject malicious shortcodes into blog comments, potentially compromising the authenticated browser context of administrators and allowing execution of arbitrary JavaScript on the site's origin.

• Compromise of authenticated browser context of administrators viewing affected articles
• Execution of arbitrary JavaScript on the site's origin
• Potential for phishing or further exploitation through embedded contact forms

Technical summary

The vulnerability allows an unauthenticated attacker to inject malicious shortcodes into blog comments, which can execute JavaScript on the site's origin when viewed by another user. This is due to the global shortcode expansion running over the complete rendered page, including HTML-escaped blog comments. The flaw can compromise the authenticated browser context of an administrator who views the affected article. Other registered shortcodes also expand in comments; Mail.getForm can embed a working contact form with a valid CSRF token.

Defensive priority

Defenders should prioritize patching or mitigating this vulnerability, especially for sites with public commenting enabled.

Recommended defensive actions

• Patch baserCMS to version 5.3.2 or 5.4.2
• Review and clean up existing blog comments for malicious shortcodes
• Implement additional security measures for public commenting sections
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and source item provide details on the vulnerability, affected versions, and patched versions. The vulnerability allows an unauthenticated attacker to inject malicious shortcodes into blog comments, which can execute JavaScript on the site's origin when viewed by another user. This is due to the global shortcode expansion running over the complete rendered page, including HTML-escaped blog comments. The CVE record was published on 2026-10-23T14:00:33.254Z and has not been modified since then.

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.