PT-2026-33970 · Mozilla · Firefox

Published 2026-04-21 · Updated 2026-04-21 · CVE-2026-6784

Mitre

CVSS v3.1

7.5

High

AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Memory safety bugs present in Firefox 149 and Thunderbird 149. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 150.

Fix

Memory Corruption

Use After Free

Out of bounds Read

Weakness Enumeration

CWE-787

CWE-416

CWE-125

Related Identifiers

CVE-2026-6784

Affected Products

Firefox

References · 3

• https://nvd.nist.gov/vuln/detail/CVE-2026-6784 · Security Note
• https://mozilla.org/security/advisories/mfsa2026-30 · Vendor Advisory
• https://bugzilla.mozilla.org/buglist.cgi?bug_id=1536243%2C1745382%2C1851073%2C1893400%2C1963301%2C2001319%2C2002899%2C2012436%2C2014435%2C2016901%2C2019916%2C2020486%2C2020612%2C2020817%2C2021788%2C2022051%2C2022367%2C2022431%2C2023302%2C2023670%2C2024225%2C2024238%2C2024240%2C2024265%2C2024367%2C2024369%2C2024424%2C2024760%2C2025281%2C2025361%2C2025387%2C2025466%2C2025954%2C2025958%2C2026278%2C2026292%2C2026297%2C2026378%2C2027148%2C2027287%2C2027341%2C2027384%2C2027427%2C2027694%2C2027993%2C2028009%2C2028270%2C2028416%2C2028524%2C2029295%2C2029301%2C2029461%2C2029699%2C2029800%2C2029801 · Note