PT-2026-61899 · Mozilla+1 · Firefox+2

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CVE-2026-16387

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Published

2026-07-21

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Updated

2026-08-31

CVSS v3.1

10

Critical

VectorAV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Name of the Vulnerable Software and Affected Versions Firefox versions prior to 153 Firefox ESR versions prior to 140.13 Thunderbird versions prior to 153 Thunderbird versions prior to 140.13
Description A site isolation issue exists within the Networking component.
Recommendations Update Firefox to version 153 or later. Update Firefox ESR to version 140.13 or later. Update Thunderbird to version 153 or later. Update Thunderbird to version 140.13 or later.

Fix

DoS

Improper Access Control

Information Disclosure

Origin Validation Error

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Weakness Enumeration

Related Identifiers

ALSA-2026:47101
ALSA-2026:47104
ALSA-2026:47105
ALSA-2026:49621
ALSA-2026:49921
ALSA-2026:49922
CVE-2026-16387
OESA-2026-3195
OESA-2026-3196
OESA-2026-3225
OESA-2026-3226
OESA-2026-3227
OESA-2026-3228
OPENSUSE-SU-2026:11329-1
OPENSUSE-SU-2026:11358-1
OPENSUSE-SU-2026:11359-1
OPENSUSE-SU-2026:21519-1
OPENSUSE-SU-2026:21713-1
SUSE-SU-2026:23115-1
SUSE-SU-2026:23137-1
SUSE-SU-2026:23411-1
SUSE-SU-2026:3200-1
SUSE-SU-2026:3221-1
SUSE-SU-2026:3546-1

Affected Products

Firefox
Rocky Linux
Thunderbird