Description
DeepSeek R1 through V3.1 allows XSS, as demonstrated by JavaScript execution in the context of the run-html-chat.deepseeksvc.com domain. NOTE: some third parties have indicated that this is intended behavior.
Affected products
deepseek: deepseek-r1; deepseek: deepseek-v2; deepseek: deepseek-v3
References3
- hackmd.io/@MrqrFIlhQFi7vUwkqbrXDw/deepseek ExploitThird Party Advisory
- youtu.be/IgQwy52FVT4 Exploit
- deepseek.com Permissions Required
Metrics
- CVSS 3.1
-
8.8
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - EPSS — exploit probability
- 1% percentile: 49 · as of 8 November 2026
- CWE
- CWE-79
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.