CVE-2026-8956
published 2026-05-19CVE-2026-8956: Integer overflow in the Networking: JAR component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
PriorityP349critical9.8CVSS 3.1
AVNACLPRNUINSUCHIHAH
EPSS
0.60%
45.0th percentile
Integer overflow in the Networking: JAR component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
Affected
10 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| mozilla | firefox | < Firefox 151 | Firefox 151 |
| mozilla | firefox | < 140.11.0 | 140.11.0 |
| mozilla | firefox | < 151.0.0 | 151.0.0 |
| mozilla | firefox | — | — |
| mozilla | firefox_esr | < Firefox ESR 140.11 | Firefox ESR 140.11 |
| mozilla | thunderbird | < Thunderbird 140.11 | Thunderbird 140.11 |
| mozilla | thunderbird | < Thunderbird 151 | Thunderbird 151 |
| mozilla | thunderbird | < 140.11 | 140.11 |
| mozilla | thunderbird | < 151.0.0 | 151.0.0 |
| rhel10 | firefox-flatpak | — | — |
CVSS provenance
nvdv3.19.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
vendor_redhat9.8CRITICAL
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VulDB
Mozilla Firefox up to 140.10/150 JAR integer overflow
vuldb·2026-05-19·CVSS 9.8
CVE-2026-8956 [CRITICAL] Mozilla Firefox up to 140.10/150 JAR integer overflow
A vulnerability was found in Mozilla Firefox up to 140.10/150 and classified as critical. This issue affects some unknown processing of the component JAR. Such manipulation leads to integer overflow.
This vulnerability is documented as CVE-2026-8956. The attack can be executed remotely. There is not any exploit available.
It is suggested to upgrade the affected component.
GHSA
GHSA-22h3-6xv6-p2px: Integer overflow in the Networking: JAR component
ghsa_unreviewed·2026-05-19
CVE-2026-8956 [CRITICAL] CWE-190 GHSA-22h3-6xv6-p2px: Integer overflow in the Networking: JAR component
Integer overflow in the Networking: JAR component. This vulnerability was fixed in Firefox 151 and Firefox ESR 140.11.
Red Hat
firefox: Integer overflow in the Networking: JAR component
vendor_redhat·2026-05-19·CVSS 9.8
CVE-2026-8956 [CRITICAL] CWE-190 firefox: Integer overflow in the Networking: JAR component
firefox: Integer overflow in the Networking: JAR component
A flaw was found in Firefox. The Mozilla Foundation's Security Advisory describes the following issue:
Integer overflow in the Networking: JAR component
Statement: Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory.
Package: firefox (Red Hat Enterprise Linux 10) - Affected
Package: rhel10/firefox-flatpak (Red Hat Enterprise Linux 10) - Affected
Package: firefox (Red Hat Enterprise Linux 6) - Out of support scope
Package: firefox (Red Hat Enterprise Linux 7) - Affected
Package: firefox (Red Hat Enterprise Linux 8) - Affected
Package: firefox (Red Hat Enterprise Linux 9) - Affected
Mozilla
Mozilla Foundation Security Advisory 2026-48: CVE-2026-8956
vendor_mozilla·CVSS 9.8
CVE-2026-8956 [CRITICAL] Mozilla Foundation Security Advisory 2026-48: CVE-2026-8956
Mozilla Foundation Security Advisory 2026-48
CVE: CVE-2026-8956
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 140.11
Mozilla
Mozilla Foundation Security Advisory 2026-51: CVE-2026-8956
vendor_mozilla·CVSS 9.8
CVE-2026-8956 [CRITICAL] Mozilla Foundation Security Advisory 2026-51: CVE-2026-8956
Mozilla Foundation Security Advisory 2026-51
CVE: CVE-2026-8956
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 140.11
Mozilla
Mozilla Foundation Security Advisory 2026-50: CVE-2026-8956
vendor_mozilla·CVSS 9.8
CVE-2026-8956 [CRITICAL] Mozilla Foundation Security Advisory 2026-50: CVE-2026-8956
Mozilla Foundation Security Advisory 2026-50
CVE: CVE-2026-8956
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 151
Mozilla
Mozilla Foundation Security Advisory 2026-46: CVE-2026-8956
vendor_mozilla·CVSS 9.8
CVE-2026-8956 [CRITICAL] Mozilla Foundation Security Advisory 2026-46: CVE-2026-8956
Mozilla Foundation Security Advisory 2026-46
CVE: CVE-2026-8956
Product: Firefox
Impact: high
Fixed in: Firefox 151
No detection rules found.
No public exploits indexed.
2026-05-19
Published