CVE-2021-23957

published 2021-02-26

CVE-2021-23957: Navigations through the Android-specific `intent` URL scheme could have been misused to escape iframe sandbox. Note: This issue only affected Firefox for…

Priority P2 73 high 7.4 CVSS 3.1

AV N AC L PR N UI R S C C N I H A N

ITW VulnCheck KEV

Navigations through the Android-specific `intent` URL scheme could have been misused to escape iframe sandbox. Note: This issue only affected Firefox for Android. Other operating systems are unaffected. This vulnerability affects Firefox < 85.

Affected

4 ranges

Vendor	Product	Version range	Fixed in
debian	firefox	—	—
mozilla	firefox	< 85	85
mozilla	firefox	< 85.0	85.0
mozilla	firefox	—	—

Detection & IOCs extracted from sources · hover to see the quote

• → Monitor for navigations using the Android `intent` URL scheme originating from within an iframe context in Firefox for Android, which may indicate an attempt to escape iframe sandbox restrictions. ↗

• · This vulnerability only affects Firefox for Android (versions < 85); all other operating systems are unaffected, so detection efforts should be scoped exclusively to Firefox for Android deployments. ↗

CVSS provenance

nvd v3.1 7.4 HIGH CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:N

nvd v2.0 4.3 MEDIUM AV:N/AC:M/Au:N/C:N/I:P/A:N

vulncheck 7.4 HIGH

vendor_debian 7.4 LOW

CVEs like this are exactly what “Exploited This Week” covers.

Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.