What is CVE-2026-12328?

CVE-2026-12328 is a high-severity vulnerability in Mozilla Firefox, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 8.1/10. Published 2026-06-16.

How severe is CVE-2026-12328?

High severity. CVSS v3 base score is 8.1 out of 10.

Buffer overflow in Mozilla Firefox

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. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these cou…

Vulnerability class: Buffer Overflow

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Mozilla Firefox — versions 115.37, 140.12, 152
Mozilla Thunderbird — versions 140.12, 152

Weakness classification (CWE)

CWE-120 — Buffer Copy without Checking Size of Input (Classic Buffer Overflow)

References

Frequently asked questions

What is CVE-2026-12328?: CVE-2026-12328 is a high-severity vulnerability in Mozilla Firefox, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 8.1/10. Published 2026-06-16.
How severe is CVE-2026-12328?: High severity. CVSS v3 base score is 8.1 out of 10.