CVE-2025-8042Public exploitNetwork attack vector

Cross-site downloads via omitted sandbox classification

Published Aug 19, 2025 · Updated Apr 13, 2026

Sandbox bypass in Firefox for Android before 141 allows remote attackers to start cross-site downloads from restricted iframes. GeckoViewExternalAppService omitted the desktop classifyDownloads call, so requests lacking allow-downloads reached external download handling. Opening attacker-controlled content is enough to show a download prompt, but a user must approve the download before the file is saved.

CVSS severity9.8
Critical
EPSS probability0.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Sandbox bypass in Firefox for Android before 141 allows remote attackers to start cross-site downloads from restricted iframes. GeckoViewExternalAppService omitted the desktop classifyDownloads call, so requests lacking allow-downloads reached external download handling. Opening attacker-controlled content is enough to show a download prompt, but a user must approve the download before the file is saved.

The record

CVE
CVE-2025-8042
Published
Aug 19, 2025
Updated
Apr 13, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-732, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 19, 2025CVE publishedPublication date reported by the CVE source.
  2. Apr 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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.

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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 exploitPublished

Weakness, pattern, technique

CWE-732Incorrect Permission Assignment for Critical Resource
T1189Drive-by Compromise

Public exploit references

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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