CVE-2026-8949

7.5 HIGH

Integer overflow in the Widget: Win32 component

Published: 2026-05-19 · Last updated: 2026-05-20

Severity and scoring

CVSS: 7.5 HIGH
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE: CWE-190

Affected products

Vendor	Product
mozilla	firefox, thunderbird

Description

Integer overflow in the Widget: Win32 component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

Source: NVD

References

[NVD]https://nvd.nist.gov/vuln/detail/CVE-2026-8949
[Other]https://bugzilla.mozilla.org/show_bug.cgi?id=1355639
[Vendor advisory]https://www.mozilla.org/security/advisories/mfsa2026-46/
[Vendor advisory]https://www.mozilla.org/security/advisories/mfsa2026-48/
[Vendor advisory]https://www.mozilla.org/security/advisories/mfsa2026-50/
[Vendor advisory]https://www.mozilla.org/security/advisories/mfsa2026-51/

Related CVEs

Same vendor

CVE-2026-12330 — Incorrect boundary conditions in the Internationalization component (5.4 MEDIUM)
CVE-2026-12329 — Memory safety bug fixed in Thunderbird ESR 140.12 (5.3 MEDIUM)
CVE-2026-12328 — Memory safety bugs present in Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird ESR 140.11, Firefox 151 and Thunderbird 151 (8.1 HIGH)
CVE-2026-12323 — Spoofing issue in the DOM: Core & HTML component (5.4 MEDIUM)
CVE-2026-12322 — Clickjacking issue in the Widget: Gtk component (5.4 MEDIUM)

Same CWE

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CVE-2026-52722 — A signed integer overflow vulnerability was found in GStreamer's VMnc decoder (7.1 HIGH)
CVE-2025-55647 — An Out-of-Memory in the mp4_mux_cenc_insert_pssh function (filters/mux_isom.c) of GPAC MP4Box v2.4 allows attackers to cause a Denial of ... (5.5 MEDIUM)
CVE-2026-6045 — LibreOffice can import EMF+ graphics, which may be embedded in documents