CVE-2025-26210Public exploitNetwork attack vector

JavaScript execution via generated webpage eval

Published Sep 3, 2025 · Updated Sep 8, 2025

Cross-site scripting in DeepSeek R1 through V3.1 allows remote attackers to execute JavaScript on run-html-chat.deepseeksvc.com. The demonstrated generated page's form-submit handler interpolates an input value directly into eval(), and the hosted preview executes the resulting code under a DeepSeek-controlled origin. Exploitation requires a user to request and run an insecure generated webpage and submit a payload; the CVE record is disputed because some third parties classify this execution as intended behavior.

CVSS severity8.8
High
EPSS probability0.58%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in DeepSeek R1 through V3.1 allows remote attackers to execute JavaScript on run-html-chat.deepseeksvc.com. The demonstrated generated page's form-submit handler interpolates an input value directly into eval(), and the hosted preview executes the resulting code under a DeepSeek-controlled origin. Exploitation requires a user to request and run an insecure generated webpage and submit a payload; the CVE record is disputed because some third parties classify this execution as intended behavior.

The record

CVE
CVE-2025-26210
Published
Sep 3, 2025
Updated
Sep 8, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 3, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 8, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
9.8GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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