Telegram Desktop before 6.9.4 allows XSS in the HTML exporter. (The first fixed stable version is 7.0.1.) This occurs in button.text.toUtf8 in export_output_html.cpp. Exploitation cannot occur unless HTML export was used by a victim. However, the exploit payload can be exported if a message were forwarded into a group by a member (it is not necessary for the message author to be a member of a group).
Attack Parameters
Attack Vector
Local
Requires local access
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
Active
User action required
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
None
No disruption
CVSS Vector v4.0
Weakness Type (CWE)
References 6
https://expatch.com/writeups/telegram-html-export-xss.html
cve@mitre.org
https://github.com/telegramdesktop/tdesktop/blob/v6.9.3/Telegram/SourceFiles/ex…
cve@mitre.org
https://github.com/telegramdesktop/tdesktop/commit/52c779bffa8dde3c5c09826add26…
cve@mitre.org
https://github.com/telegramdesktop/tdesktop/commit/8457d13aa795fadf99c955d2a04f…
cve@mitre.org
https://github.com/telegramdesktop/tdesktop/releases/tag/v6.9.4
cve@mitre.org
https://thehackernews.com/2026/09/telegram-desktop-flaw-lets-hidden.html
cve@mitre.org