CVE-2026-0881Network attack vector

Sandbox escape via unvalidated BackupUI actor messages

Published Jan 13, 2026 · Updated Jan 13, 2026

Sandbox escape in Mozilla Firefox before 147 allows attackers controlling a content process to invoke privileged backup operations. The BackupUI actor accepts messages from unprivileged Spotlight documents without verifying that the sending process has a privileged remote type. Exploitation requires control of a content process and enables access to backup state and operations, including profile restoration and backup encryption changes.

CVSS severity10.0
Critical
EPSS probability0.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Sandbox escape in Mozilla Firefox before 147 allows attackers controlling a content process to invoke privileged backup operations. The BackupUI actor accepts messages from unprivileged Spotlight documents without verifying that the sending process has a privileged remote type. Exploitation requires control of a content process and enables access to backup state and operations, including profile restoration and backup encryption changes.

The record

CVE
CVE-2026-0881
Published
Jan 13, 2026
Updated
Jan 13, 2026
Vendor
Mozilla
Product
Firefox
Classifications
CWE-284, CWE-693, T1068
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

Published CVSS scores

10.0CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

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-284Improper Access Control
CWE-693Protection Mechanism Failure
T1068Exploitation for Privilege Escalation

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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