Discourse Image Pipeline Exploit Chains JPEG Race, GhostScript and ImageMagick for File Read

A Discourse image upload exploit allowed basic users to read server files by chaining a JPEG processing delay, Ghostscript execution, and ImageMagick features. The research also exposed a separate cache poisoning flaw that could run JavaScript for anonymous visitors. Researchers reported both issues in June 2026 and patched them before publication. The technical report from Searchlight Cyber describes testing against default configurations. Discourse powers more than 22,000 communities, making its upload handling a valuable security target. The findings are independent of Hacktron’s OpenAI research, which involved different image decoder and sign-on bugs, previously covered by Cybersecurity News. The file read chain required...

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