Firefox for iOS: Protection Mechanism Failure
CVE-2025-54143 is a critical-severity protection mechanism failure vulnerability in Firefox for iOS from Mozilla, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 0.51% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Firefox to 141.0 or a later version.
- Read the advisory on mozilla.org for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Mozilla | Firefox for iOS | Not specified in the record | Not stated |
| Mozilla | Firefox | before 141.0 | 141.0 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CISA (ADP).
Official description
Sandboxed iframes on webpages could potentially allow downloads to the device, bypassing the expected sandbox restrictions declared on the parent page. This vulnerability was fixed in Firefox for iOS 141.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Protection Mechanism Failure
The product does not use or incorrectly uses a protection mechanism that provides sufficient defense against directed attacks against the product.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
- bugzilla.mozilla.org/show_bug.cgi?id=1912671Issue Tracking, Permissions Required
Other vulnerabilities in Firefox for iOS
- 8.8 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 7.5 High severity
- 9.1 Critical severity
- 9.1 Critical severity
Recent Protection Mechanism Failure vulnerabilities
- 7.0 High severity
- 9.1 Critical severity
- 9.8 Critical severity
- 8.1 High severity
- 7.7 High severity
- 8.8 High severity
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