CVE-2025-54143 | Sandboxed iframes could allow local downloads despite sandbox restrictions

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.

Published: 2025-08-19 Last update: 2026-04-13 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-54143 is rated Moderate Risk (47.4/100): CVSS Critical severity, with low exploitation likelihood (EPSS 0.08%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-54143

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-08-21 0.02% 0.08% +0.06%
2 2025-08-20 — 0.02% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-54143

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.9 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2025-54143

OS Trackers for CVE-2025-54143

vendor priority summary link
alpine — CVE-2025-54143: 1 source package rows (firefox); 114 state rows across 2 repos (3.22-community, edge-community); fixed 0, open 114. https://security.alpinelinux.org/vuln/CVE-2025-54143
ubuntu medium CVE-2025-54143 medium priority: Ubuntu including 2 source packages (firefox, thunderbird), 8 status rows across 4 suites (jammy, noble, plucky, upstream): not-affected 8. https://ubuntu.com/security/CVE-2025-54143

Affected software / configurations for CVE-2025-54143

Vendor Product Version Raw CPE
mozilla firefox < 141.0 cpe:2.3:a:mozilla:firefox:*:*:*:*:*:iphone_os:*:*

References for CVE-2025-54143

cvelogic Threat Intelligence