Critical severity · published May 11, 2026
CVE-2026-43900
DeepChat: Persistent DOM XSS via HTML Entity Encoding in `<antArtifact>` SVG Rendering (Bypass of `svgSanitizer.ts`)
9.3
CVSS
0.4%
EPSS
No
On KEV
Description
DeepChat is an open-source artificial intelligence agent platform that unifies models, tools, and agents. Prior to v1.0.4-beta.1, a Cross-Site Scripting (XSS) vulnerability exists due to a discrepancy between the backend validation layer and the frontend browser rendering engine. The SVGSanitizer (src/main/lib/svgSanitizer.ts) restricts script execution by scrubbing javascript: protocols using plain-text regular expressions. However, it fails to account for HTML entity decoding prior to Vue's v-html DOM insertion inside the SvgArtifact.vue component. By feeding an SVG artifact with obfuscated entities (e.g., javascript:alert(1)), an attacker can completely bypass the sanitizer, culminating in arbitrary JavaScript execution when a victim interacts with the rendered SVG Element. This vulnerability is fixed in v1.0.4-beta.1.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
High
Integrity
High
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 31% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
DE
deepchat · ThinkInAIXYZ
< 1.0.4-beta.1 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-43900
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-43900
github.com
https://github.com/ThinkInAIXYZ/deepchat/security/advisories/GHSA-7r59-67v3-3mgp
More from deepchat
9.6
CVE-2026-43899
DeepChat: Incomplete Fix for CVE-2025-55733 leads to Remote Code Execution via Markdown Links bypassing `isValidExternalUrl`
9.6
CVE-2025-67744
Mermaid XSS vulnerability leads to Remote Code Execution
9.6
CVE-2025-66481
DeepChat's Incomplete XSS Fix Allows RCE through Mermaid Content
9.6
CVE-2025-66222
DeepChat Cross-Site Scripting(XSS) escalate to Remote Code Execution(RCE)
