CVE-2025-54143Network attack vector

Unauthorized downloads via sandboxed iframe bypass

Published Aug 19, 2025 · Updated Apr 13, 2026

Protection mechanism failure in Firefox for iOS before 141 allows remote attackers to download files through sandboxed iframes. Firefox's iframe sandbox enforcement permits a device download despite a parent-page declaration intended to prohibit that action. The trigger is webpage content containing such an iframe; Mozilla has not published the responsible handler, and the reported consequence stops at a local download.

CVSS severity9.8
Critical
EPSS probability0.48%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Protection mechanism failure in Firefox for iOS before 141 allows remote attackers to download files through sandboxed iframes. Firefox's iframe sandbox enforcement permits a device download despite a parent-page declaration intended to prohibit that action. The trigger is webpage content containing such an iframe; Mozilla has not published the responsible handler, and the reported consequence stops at a local download.

The record

CVE
CVE-2025-54143
Published
Aug 19, 2025
Updated
Apr 13, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-693
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 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-693Protection Mechanism Failure

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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