Description
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).
References6
- expatch.com/writeups/telegram-html-export-xss.html
- github.com/telegramdesktop/tdesktop/blob/v6.9.3/Telegram/Source…
- github.com/telegramdesktop/tdesktop/commit/52c779bffa8dde3c5c09…
- github.com/telegramdesktop/tdesktop/commit/8457d13aa795fadf99c9…
- github.com/telegramdesktop/tdesktop/releases/tag/v6.9.4
- thehackernews.com/2026/09/telegram-desktop-flaw-lets-hidden.html
Metrics
- CVSS 3.1
-
8.2
HIGH
Score source: CNA
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N - CVSS 4.0
-
8.3
HIGH
Score source: CNA
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 3 · as of 8 November 2026
- CWE
- CWE-79
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