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PatchSiren cyber security CVE debrief

CVE-2026-43934 e107inc CVE debrief

A Broken Access Control vulnerability in e107 CMS prior to version 2.3.4 allows authenticated users to edit comments posted by other users. The flaw stems from insufficient server-side validation, where the application relies solely on a predictable identifier in the request to determine which comment to edit without verifying that the requesting user owns the target comment. The vulnerability was disclosed on 2026-05-26 and carries a CVSS 3.1 score of 6.5 (Medium severity). The issue has been resolved in e107 version 2.3.4.

Vendor
e107inc
Product
e107
CVSS
MEDIUM 6.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-26
Original CVE updated
2026-05-26
Advisory published
2026-05-26
Advisory updated
2026-05-26

Who should care

Organizations running e107 CMS versions prior to 2.3.4, particularly those with multi-user comment environments where content integrity is critical. Security teams should prioritize patching to prevent unauthorized content modification that could enable misinformation campaigns, defacement, or reputational damage.

Technical summary

The e107 CMS comment editing functionality fails to validate that the authenticated user owns the comment being modified. The application accepts a comment identifier from the request and processes the edit without server-side verification of ownership, relying only on the identifier's presence. This allows any authenticated user to manipulate the identifier to target comments posted by other users. The vulnerability is classified under CWE-284 (Improper Access Control) and CWE-639 (Authorization Bypass Through User-Controlled Key). The fix in version 2.3.4 implements proper ownership validation before permitting comment modifications.

Defensive priority

medium

Recommended defensive actions

  • Upgrade e107 CMS to version 2.3.4 or later to remediate this vulnerability
  • Review and implement proper server-side access control checks for all comment modification operations
  • Ensure ownership verification is performed for any resource modification requests, not just identifier-based lookups
  • Audit application logs for any unauthorized comment modifications prior to patching
  • Consider implementing additional authorization middleware for comment management endpoints

Evidence notes

The vulnerability description indicates the application uses a predictable identifier for comment editing operations without proper ownership verification. The CVSS vector (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N) confirms network-based attack vector with low attack complexity, requiring low privileges but no user interaction, with high impact to integrity. CWE-284 (Improper Access Control) and CWE-639 (Authorization Bypass Through User-Controlled Key) are identified as relevant weakness classifications.

Official resources

2026-05-26T16:16:25.253Z