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Vulnerability record · CVE-2024-1563 · published 22 February 2024

CVE-2024-1563: Mozilla firefox focus toctou race condition vulnerability

Mozilla · Firefox Focus

An attacker could have executed unauthorized scripts on top origin sites using a JavaScript URI when opening an external URL with a custom Firefox scheme and a timeout race condition. This vulnerability affects Focus for iOS < 122.

8.1 CVSS 3.1 High EPSS 0.39% · top 69.8% CWE-367 · TOCTOU race condition
8.1CVSS 3.1 base score
0.39%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References
17 Jun 2026Last modified by NVD

Description

An attacker could have executed unauthorized scripts on top origin sites using a JavaScript URI when opening an external URL with a custom Firefox scheme and a timeout race condition. This vulnerability affects Focus for iOS < 122.

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://bugzilla.mozilla.org/show_bug.cgi?id=1863831 Issue Tracking
https://www.mozilla.org/security/advisories/mfsa2024-09/ Vendor Advisory
https://bugzilla.mozilla.org/show_bug.cgi?id=1863831 Issue Tracking
https://www.mozilla.org/security/advisories/mfsa2024-09/ Vendor Advisory

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Source: NIST National Vulnerability Database (record CVE-2024-1563), CISA KEV, FIRST EPSS (scores of 2026-09-29). This page is refreshed as NVD updates the record.