CVE-2025-10535

Private-tab disclosure via custom-tab state overwrite

Published Sep 16, 2025 · Updated Sep 16, 2025

Mitigation bypass in Firefox for Android 142 allows physically proximate attackers to view private tabs after an app switch. During initialization, DefaultBrowsingModeManager lets a custom tab rewrite appstate.mode instead of preserving the private-browsing state. Exposure requires the screen-lock option, Firefox as the default custom-tab handler, an open private tab, and physical access after the app switch.

CVSS severity7.5
High
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Mitigation bypass in Firefox for Android 142 allows physically proximate attackers to view private tabs after an app switch. During initialization, DefaultBrowsingModeManager lets a custom tab rewrite appstate.mode instead of preserving the private-browsing state. Exposure requires the screen-lock option, Firefox as the default custom-tab handler, an open private tab, and physical access after the app switch.

The record

CVE
CVE-2025-10535
Published
Sep 16, 2025
Updated
Sep 16, 2025
Vendor
Mozilla
Product
Firefox
Classifications
CWE-200
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 16, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2025Record 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 <143

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=unspecified <143

Published CVSS scores

7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/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.

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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)
Vectorphysical
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-200Exposure of Sensitive Information to an Unauthorized Actor

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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