CVE-2026-8956 | Integer overflow in the Networking: JAR component. This vuln… | CVSS 9.8 CRITICAL

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.

Metadata

CVE ID: CVE-2026-8956
State: PUBLISHED
Assigner: mozilla
Reserved: 2026-05-19 12:29 UTC
Published: 2026-05-19 12:29 UTC
Last updated: 2026-05-19 17:10 UTC
Primary CWE: CWE-190
CWE-190 Integer Overflow or Wraparound
Vendor / Product: Mozilla / Firefox
Sources: cve.org · NVD

Severity & Metrics

9.8 CRITICAL CVSS 3.1

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

SSVC — CISA Coordinator

Exploitation: none
Automatable: yes
Tech. Impact: total

Affected products (2)

Vendor	Product	Platform	Versions
Mozilla	Firefox	—	140.11 ≤ 140., 151 ≤
Mozilla	Thunderbird	—	140.11 ≤ 140., 151 ≤

Weakness (CWE)

CWE	Source	Description
CWE-190	adp	CWE-190 Integer Overflow or Wraparound

CVSS scores (1)

Score	Severity	Version	Source	Vector
9.8	CRITICAL	3.1	adp	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References (5)