Vulnerability · Published Aug 19, 2025 · Assigned by mozilla
CVE-2025-54143Sandboxed iframes could allow local downloads despite sandbox restrictions
Critical 9.8
In plain English
A critical-severity security flaw in Firefox for iOS from Mozilla. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 42% of all known vulnerabilities).
Severity (CVSS 3.1)9.8Critical
Exploit odds (30 days)0.5%top 58.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu:22.04:LTS | mozjs102 | no fix listed | UBUNTU-CVE-2025-54143 |
| Ubuntu:24.04:LTS | mozjs102 | no fix listed | UBUNTU-CVE-2025-54143 |
| Ubuntu:24.04:LTS | mozjs115 | no fix listed | UBUNTU-CVE-2025-54143 |
| Ubuntu:22.04:LTS | mozjs78 | no fix listed | UBUNTU-CVE-2025-54143 |
| Ubuntu:22.04:LTS | mozjs91 | no fix listed | UBUNTU-CVE-2025-54143 |
| Ubuntu:22.04:LTS | thunderbird | no fix listed | UBUNTU-CVE-2025-54143 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox for iOS | see references |
Weakness: CWE-693 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H