CVE-2026-0887Network attack vector

Information disclosure via PDF Viewer clickjacking

Published Jan 13, 2026 · Updated Jan 13, 2026

Clickjacking in Mozilla Firefox before 147 and Firefox ESR before 140.7 allows remote attackers to disclose PDF Viewer information. Mozilla identifies the PDF Viewer as the affected component but has not published the request, interface element, or state that exposes data when framed. Exploitation requires user interaction with attacker-controlled web content and affects confidentiality only; the public record does not identify the disclosed data.

CVSS severity4.3
Medium
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Clickjacking in Mozilla Firefox before 147 and Firefox ESR before 140.7 allows remote attackers to disclose PDF Viewer information. Mozilla identifies the PDF Viewer as the affected component but has not published the request, interface element, or state that exposes data when framed. Exploitation requires user interaction with attacker-controlled web content and affects confidentiality only; the public record does not identify the disclosed data.

The record

CVE
CVE-2026-0887
Published
Jan 13, 2026
Updated
Jan 13, 2026
Vendor
Mozilla
Product
Firefox
Classifications
CWE-497
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 13, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 13, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=unspecified <147

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=unspecified <147
Mozilla · Firefox ESRversion=unspecified <140.7

Published CVSS scores

4.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-497Exposure of Sensitive System Information to an Unauthorized Control Sphere

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo