CVE-2026-121560 PUBLISHED

LogChimp 0.9.0-alpha.1 before 0.9.3 contains an authorization bypass vulnerability that allows authenticated post authors to modify any other post by supplying mismatched postId and id body parameters. Attackers can set postId to their own post and id to an enumerated victim post UUID to overwrite its title, slug, content, boardId and roadmap_id.

• leediay153 from Viettel Post finder
• mittalyashu remediation developer

• Patch Commit
• https://github.com/logchimp/logchimp
• https://github.com/logchimp/logchimp/blob/v0.9.2/packages/server/src/controllers/post/updatePost.ts#L67
• https://github.com/logchimp/logchimp/blob/v0.9.2/packages/server/src/middlewares/postExists.ts#L72-L77
• logchimp v0.9.3 Release Notes
• VulnCheck Advisory: LogChimp before 0.9.3 Authorization Bypass via PATCH /api/v1/posts

• Authorization Bypass Through User-Controlled Key CWE