CVE-2026-8949
published 2026-05-19CVE-2026-8949: Integer overflow in the Widget: Win32 component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
PriorityP341high7.5CVSS 3.1
AVNACLPRNUINSUCNINAH
EPSS
0.58%
44.0th percentile
Integer overflow in the Widget: Win32 component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
Affected
12 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 151 | Thunderbird 151 |
| mozilla | thunderbird | < Thunderbird 140.11 | Thunderbird 140.11 |
| mozilla | thunderbird | < 140.11 | 140.11 |
| mozilla | thunderbird | < 151.0.0 | 151.0.0 |
| mozilla | thunderbird | — | — |
| rhel10 | firefox-flatpak | — | — |
| rhel10 | thunderbird-flatpak | — | — |
CVSS provenance
nvdv3.17.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
vendor_redhat7.5HIGH
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VulDB
Mozilla Firefox up to 150 Win32 integer overflow
vuldb·2026-05-19·CVSS 7.5
CVE-2026-8949 [HIGH] Mozilla Firefox up to 150 Win32 integer overflow
A vulnerability categorized as critical has been discovered in Mozilla Firefox up to 150. Impacted is an unknown function of the component Win32 Component. Executing a manipulation can lead to integer overflow.
This vulnerability is handled as CVE-2026-8949. The attack can be executed remotely. There is not any exploit available.
It is advisable to upgrade the affected component.
GHSA
GHSA-wpxg-v53p-m79m: Integer overflow in the Widget: Win32 component
ghsa_unreviewed·2026-05-19
CVE-2026-8949 [HIGH] CWE-190 GHSA-wpxg-v53p-m79m: Integer overflow in the Widget: Win32 component
Integer overflow in the Widget: Win32 component. This vulnerability was fixed in Firefox 151 and Firefox ESR 140.11.
Red Hat
firefox: thunderbird: Integer overflow in the Widget: Win32 component
vendor_redhat·2026-05-19·CVSS 7.5
CVE-2026-8949 [HIGH] CWE-190 firefox: thunderbird: Integer overflow in the Widget: Win32 component
firefox: thunderbird: Integer overflow in the Widget: Win32 component
Integer overflow in the Widget: Win32 component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
A flaw was found in Firefox and Thunderbird. The Mozilla Foundation's Security Advisory describes the following issue:
Integer overflow in the Widget: Win32 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: rhel10/thunderbird-flatpak (Red Hat Enterprise Linux 10) - Affected
Package: thunderbird (Red Hat Enterprise Linux 10) - Affected
Pac
Mozilla
Mozilla Foundation Security Advisory 2026-50: CVE-2026-8949
vendor_mozilla·CVSS 7.5
CVE-2026-8949 [HIGH] Mozilla Foundation Security Advisory 2026-50: CVE-2026-8949
Mozilla Foundation Security Advisory 2026-50
CVE: CVE-2026-8949
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 151
Mozilla
Mozilla Foundation Security Advisory 2026-48: CVE-2026-8949
vendor_mozilla·CVSS 7.5
CVE-2026-8949 [HIGH] Mozilla Foundation Security Advisory 2026-48: CVE-2026-8949
Mozilla Foundation Security Advisory 2026-48
CVE: CVE-2026-8949
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 140.11
Mozilla
Mozilla Foundation Security Advisory 2026-51: CVE-2026-8949
vendor_mozilla·CVSS 7.5
CVE-2026-8949 [HIGH] Mozilla Foundation Security Advisory 2026-51: CVE-2026-8949
Mozilla Foundation Security Advisory 2026-51
CVE: CVE-2026-8949
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 140.11
Mozilla
Mozilla Foundation Security Advisory 2026-46: CVE-2026-8949
vendor_mozilla·CVSS 7.5
CVE-2026-8949 [HIGH] Mozilla Foundation Security Advisory 2026-46: CVE-2026-8949
Mozilla Foundation Security Advisory 2026-46
CVE: CVE-2026-8949
Product: Firefox
Impact: high
Fixed in: Firefox 151
No detection rules found.
No public exploits indexed.
2026-05-19
Published