Unauthorized form submission via omitted acceptance check
Published Mar 31, 2026 · Updated Mar 31, 2026
Improper authorization in baserCMS before 5.2.3 allows remote attackers to submit entries to closed mail forms through the public API. MailMessagesController::add() omits the MailFrontService::isAccepting() check that the guarded front-end controllers apply before accepting a form entry. No account is required, but a valid CSRF cookie and token pair must accompany the request; successful requests create unauthorized mail messages and enable spam or operational disruption.
Summary
What happened
Improper authorization in baserCMS before 5.2.3 allows remote attackers to submit entries to closed mail forms through the public API. MailMessagesController::add() omits the MailFrontService::isAccepting() check that the guarded front-end controllers apply before accepting a form entry. No account is required, but a valid CSRF cookie and token pair must accompany the request; successful requests create unauthorized mail messages and enable spam or operational disruption.
The record
- CVE
- CVE-2026-30878
- Published
- Mar 31, 2026
- Updated
- Mar 31, 2026
- Vendor
- baserCMS Users Community
- Product
- baserCMS
- Classifications
- CWE-285, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 31, 2026CVE publishedPublication date reported by the CVE source.
- Mar 31, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 5.2.3
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
- GitHub advisory mail-form API proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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