CVE-2025-26210: deepseek-r1 XSS — Exploit

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.

Is your site exposed to CVE-2025-26210?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

8.8

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

Affected Products

Vendor	Product	Versions
deepseek	deepseek-r1	All
deepseek	deepseek-v2	All
deepseek	deepseek-v3	All

References

Exploits

https://hackmd.io/@MrqrFIlhQFi7vUwkqbrXDw/deepseek https://youtu.be/IgQwy52FVT4

Other References

https://deepseek.com

Frequently Asked Questions

What is CVE-2025-26210? +

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. It has a CVSS v3.1 base score of 8.8 (HIGH).

How severe is CVE-2025-26210? +

CVE-2025-26210 has a CVSS v3.1 score of 8.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2025-26210? +

CVE-2025-26210 affects products from deepseek, specifically: deepseek-r1, deepseek-v2, deepseek-v3. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-26210? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-40282

WeGIA is a web manager for charitable institutions. In versions prior to 3.6.10, a Stored Cross-Site Scripting (XSS) vulnerability allows …

CVE-2026-3317

Reflected Cross-Site Scripting (XSS) vulnerability in Navigate Content Management System. The vulnerability is present in the '/blog' endpoint because user …

CVE-2025-10354

Cross-Site Scripting (XSS) vulnerability reflected in Semantic MediaWiki. This vulnerability allows an attacker to execute JavaScript code in the victim's …

CVE-2026-41456

Bludit CMS prior to commit 6732dde contains a reflected cross-site scripting vulnerability in the search plugin that allows unauthenticated attackers …

CVE-2026-40872

mailcow: dockerized is an open source groupware/email suite based on docker. In versions prior to 2026-03b, the admin dashboard's Autodiscover …

CVE-2026-40878

mailcow: dockerized is an open source groupware/email suite based on docker. In versions prior to 2026-03b, the mailcow web interface …

CVE-2025-26210