CVE-2026-43900 | DeepChat: Persistent DOM XSS via HTML Entity Encoding in `<antArtifact>` SVG Rendering (Bypass of `svgSanitizer.ts`)

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., j&#x61;vascript: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.

Published: 2026-05-11 Last update: 2026-05-12 Assigner: [email protected] Source: [email protected]
NVD Status：Deferred，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-43900 is rated Moderate Risk (41.5/100): CVSS Critical severity, with low exploitation likelihood (EPSS 0.04%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-43900

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-12 — 0.04% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-43900

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.3 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 5.8 [email protected]

Weakness enumeration for CVE-2026-43900

Affected software / configurations for CVE-2026-43900

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-43900

cvelogic Threat Intelligence