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Telegram Desktop Flaw Lets Hidden JavaScript Exfiltrate Messages From HTML Exports

Telegram Desktop HTML export XSS (CVSS 8.2) let bot messages exfiltrate exported chats; fixed in 7.0.1 but old exports stay vulnerable.

ExPatch researchers found that Telegram Desktop versions 4.15.1 (March 2024) through 6.9.3 wrote bot inline-keyboard button text into HTML chat exports without escaping, allowing a bot to plant invisible JavaScript. When a user opened the export in a browser, the script could exfiltrate every message in that 1,000-message file, rewrite the displayed content, or fake a verification form. The flaw (rated CVSS 3.1 8.2) was fixed by commit 8457d13a in 6.9.4 beta (July 3, 2026) and 7.0.1 stable (July 14, 2026), but pre-fix exports remain dangerous since updating the app does not fix old files. No CVE identifier or Telegram security advisory exists, and no exploitation in the wild is claimed.

The Hacker Newsupdated · 1d agofirst · 1d agoVulnerability 2 sources1