CVE-2025-66521Network attack vector

Stored script execution via unsanitized certificate names

Published Dec 19, 2025 · Updated Dec 19, 2025

Stored XSS in Foxit PDF Editor Cloud before 2025-12-01 allows remote authenticated users to execute JavaScript in another user's browser. The Trusted Certificates feature stores an attacker-controlled certificate name and later inserts it into the DOM without sanitization or output encoding. Exploitation requires low-privileged access to save the name and user interaction when another user opens the Trusted Certificates view; impact is limited to that browser session.

CVSS severity6.3
Medium
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Foxit PDF Editor Cloud before 2025-12-01 allows remote authenticated users to execute JavaScript in another user's browser. The Trusted Certificates feature stores an attacker-controlled certificate name and later inserts it into the DOM without sanitization or output encoding. Exploitation requires low-privileged access to save the name and user interaction when another user opens the Trusted Certificates view; impact is limited to that browser session.

The record

CVE
CVE-2025-66521
Published
Dec 19, 2025
Updated
Dec 19, 2025
Vendor
Foxit Software
Product
Foxit PDF Editor Cloud
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 19, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 19, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=before 2025‑12‑01

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Foxit Software · Foxit PDF Editor Cloudversion=before 2025‑12‑01

Published CVSS scores

5.4NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
6.3FoxitCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:L/A:N

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007JavaScript/JScript

Public exploit references

No public exploit references are available in this record.

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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