CVE-2026-0890Network attack vector

Clipboard disclosure via persistent post-navigation paste prompt

Published Jan 13, 2026 · Updated Jan 13, 2026

Spoofing in Firefox before 147 and Firefox ESR before 140.7 allows remote attackers to expose clipboard data through a stale paste prompt. The DOM clipboard UI fails to dismiss its paste button when the active tab navigates, so pasted content is delivered to the now-inactive document. Exploitation requires user interaction with the prompt after navigation and discloses clipboard content to a document other than the visible page.

CVSS severity5.4
Medium
EPSS probability0.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Spoofing in Firefox before 147 and Firefox ESR before 140.7 allows remote attackers to expose clipboard data through a stale paste prompt. The DOM clipboard UI fails to dismiss its paste button when the active tab navigates, so pasted content is delivered to the now-inactive document. Exploitation requires user interaction with the prompt after navigation and discloses clipboard content to a document other than the visible page.

The record

CVE
CVE-2026-0890
Published
Jan 13, 2026
Updated
Jan 13, 2026
Vendor
Mozilla
Product
Firefox
Classifications
CWE-290, T1204
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

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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=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

5.4CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L

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.

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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 exploitUnconfirmed

Weakness, pattern, technique

CWE-290Authentication Bypass by Spoofing
T1204User Execution

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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