CVE-2026-12300: Memory safety bug fixed in Thunderbird 152
Memory safety bug fixed in Firefox 152. This vulnerability was fixed in Firefox 152 and Thunderbird 152.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 152 - Upgrade
Upgrade
Firefoxto a version that resolves this vulnerability.Fixed in 152 - Upgrade
Upgrade
Thunderbirdto a version that resolves this vulnerability.Fixed in 152
Event History
Peer vulnerabilities
Found alongside the following vulnerabilities.
- CVE-2026-12289
- CVE-2026-12290
- CVE-2026-12291
- CVE-2026-12292
- CVE-2026-12293
- CVE-2026-12294
- CVE-2026-12295
- CVE-2026-12296
- CVE-2026-12297
- CVE-2026-12298
- CVE-2026-12299
- CVE-2026-12300
- CVE-2026-12301
- CVE-2026-12302
- CVE-2026-12303
- CVE-2026-12304
- CVE-2026-12305
- CVE-2026-12306
- CVE-2026-12307
- CVE-2026-12308
- CVE-2026-12309
- CVE-2026-12310
- CVE-2026-12311
- CVE-2026-12312
- CVE-2026-12313
- CVE-2026-12314
- CVE-2026-12315
- CVE-2026-12316
- CVE-2026-12317
- CVE-2026-12318
- CVE-2026-12319
- CVE-2026-12320
- CVE-2026-12321
- CVE-2026-12322
- CVE-2026-12323
- CVE-2026-12324
- CVE-2026-12325
- CVE-2026-12326
- CVE-2026-12327
- CVE-2026-12328
Frequently Asked Questions
What is the severity of CVE-2026-12300?
The severity of CVE-2026-12300 is medium with a CVSS score of 5.3.
How do I fix CVE-2026-12300?
To fix CVE-2026-12300, update to Mozilla Thunderbird version 152 or later.
What type of vulnerability is CVE-2026-12300?
CVE-2026-12300 is classified as a memory safety bug that can lead to buffer overflow.
In which products was CVE-2026-12300 fixed?
CVE-2026-12300 was fixed in Mozilla Thunderbird version 152 and Mozilla Firefox version 152.
When was CVE-2026-12300 published?
CVE-2026-12300 was published on June 16, 2026.