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CVE-2025-66521VulnerabilityPublished

CVE-2025-66521: pdfonline.foxit.com · XSS or 'Cross-site Scripting'

Affects pdfonline.foxit.comSource CVE Database V5

0

Not known to be exploited · CVSS 6.3 Medium.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score
6.3Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 1% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:L/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 19 Dec 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

What to do

AI-suggested

1. Apply patches or updates from Foxit Software Inc. as soon as they become available to address this vulnerability. 2. In the interim, restrict or sanitize user input for certificate names on the server side to prevent injection of malicious scripts. 3. Implement strict Content Security Policy (CSP) headers to limit the execution of unauthorized scripts in the browser context. 4. Conduct regular security reviews and penetration testing focused on input validation and output encoding in web applications, especially those handling certificates or sensitive data. 5. Educate users about the risks of interacting with untrusted or suspicious certificate entries and encourage reporting of anomalies. 6. Monitor web application logs for unusual activity related to the Trusted Certificates feature to detect potential exploitation attempts. 7. Consider isolating or restricting access to the Trusted Certificates view to trusted administrators only, reducing the attack surface. 8. Employ web application firewalls (WAF) with rules designed to detect and block XSS payloads targeting this feature.

Description

A stored cross-site scripting (XSS) vulnerability exists in pdfonline.foxit.com within the Trusted Certificates feature. A crafted payload can be injected as the certificate name, which is later rendered into the DOM without proper sanitization. As a result, the injected script executes each time the Trusted Certificates view is loaded.

References

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