CVE-2026-8956

Integer overflow in the Networking: JAR component

Published May 19, 2026 CVSS 3.1 · 9.8 Critical EPSS < 1% KEV · Not listed
Description
Integer overflow in the Networking: JAR component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-4592-1 firefox-esr security update
Debian DLA Debian DLA DLA-4594-1 thunderbird security update
Debian DSA Debian DSA DSA-6283-1 firefox-esr security update
Debian DSA Debian DSA DSA-6288-1 thunderbird security update
History
Type Values Removed Values Added
First Time appeared Mozilla thunderbird
CPEs cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*
Vendors & Products Mozilla thunderbird
Type Values Removed Values Added
Weaknesses CWE-680
Type Values Removed Values Added
Description Integer overflow in the Networking: JAR component. This vulnerability was fixed in Firefox 151 and Firefox ESR 140.11. Integer overflow in the Networking: JAR component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
References
Type Values Removed Values Added
Weaknesses CWE-190
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Weaknesses CWE-680
Type Values Removed Values Added
First Time appeared Mozilla
Mozilla firefox
Vendors & Products Mozilla
Mozilla firefox
Type Values Removed Values Added
Description Integer overflow in the Networking: JAR component. This vulnerability was fixed in Firefox 151 and Firefox ESR 140.11.
Title Integer overflow in the Networking: JAR component
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
mozilla
Published
Updated
May 19, 2026, 5:10 PM
Reserved
May 19, 2026, 12:29 PM
Status
Analyzed
Published
May 19, 2026, 2:16 PM
Modified
Oct 14, 2026, 8:10 PM
Severity
Moderate
Public date
May 19, 2026, 12:29 PM