What is CVE-2026-84145?

CVE-2026-84145 is a high-severity vulnerability, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 7.5/10. Published 2026-09-01.

How severe is CVE-2026-84145?

High severity. CVSS v3 base score is 7.5 out of 10.

CVE-2026-84145

CVE-2026-84145

Internally found bugs present in Thunderbird 154, Thunderbird ESR 153.1 and Thunderbird ESR 140.14. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 155, Firefox ESR 115.40, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.

Vulnerability class: Buffer Overflow

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H.

Weakness classification (CWE)

CWE-119 — Improper Restriction of Operations within the Bounds of a Memory Buffer

References

Frequently asked questions

What is CVE-2026-84145?: CVE-2026-84145 is a high-severity vulnerability, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 7.5/10. Published 2026-09-01.
How severe is CVE-2026-84145?: High severity. CVSS v3 base score is 7.5 out of 10.