Clickjacking Vulnerability in Mozilla Firefox PDF Viewer Component
CVE-2026-0887

4.3MEDIUM

Key Information:

Vendor

Mozilla
Status
Firefox
Firefox Esr
Thunderbird
Vendor
CVE Published:
13 January 2026

What is CVE-2026-0887?

A clickjacking vulnerability has been identified in the PDF Viewer component of Mozilla Firefox. This flaw can enable attackers to trick users into interacting with invisible or disguised elements on a web page, potentially leading to unauthorized information disclosure. Specifically, it affects versions of Firefox prior to 147 and Firefox ESR prior to 140.7, posing risks for users who rely on these versions for secure browsing and document viewing.

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Affected Version(s)

Firefox < 147

Firefox ESR < 140.7

Thunderbird < 147

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2006500
https://www.mozilla.org/security/advisories/mfsa2026-01/
https://www.mozilla.org/security/advisories/mfsa2026-03/

CVSS V3.1

Score:
4.3
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
None
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
Required
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Lyra Rebane
JSON
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