CVE-2026-12309
published 2026-06-16CVE-2026-12309: Memory safety bug fixed in Thunderbird 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.
PriorityP433medium6.5CVSS 3.1
AVNACLPRNUINSUCLINAL
EPSS
0.24%
14.3th percentile
Memory safety bug fixed in Thunderbird 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.
Affected
8 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| mozilla | firefox | < Firefox 152 | Firefox 152 |
| mozilla | firefox | — | — |
| mozilla | firefox_esr | < Firefox ESR 140.12 | Firefox ESR 140.12 |
| mozilla | thunderbird | < Thunderbird 152 | Thunderbird 152 |
| mozilla | thunderbird | < Thunderbird 140.12 | Thunderbird 140.12 |
| mozilla | thunderbird | — | — |
| rhel10 | firefox-flatpak | — | — |
| rhel10 | thunderbird-flatpak | — | — |
CVSS provenance
nvdv3.16.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
vendor_redhat6.5MEDIUM
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Red Hat
firefox: thunderbird: Memory safety bug fixed in Thunderbird ESR 140.12
vendor_redhat·2026-06-16·CVSS 6.5
CVE-2026-12309 [MEDIUM] CWE-825 firefox: thunderbird: Memory safety bug fixed in Thunderbird ESR 140.12
firefox: thunderbird: Memory safety bug fixed in Thunderbird ESR 140.12
Memory safety bug fixed in Firefox 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.
A flaw was found in Firefox and Thunderbird. The Mozilla Foundation's Security Advisory describes the following issue:
Memory safety bug fixed in Thunderbird ESR 140.12
Statement: Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory.
Package: firefox (Red Hat Enterprise Linux 10) - Affected
Package: rhel10/firefox-flatpak (Red Hat Enterprise Linux 10) - Affected
Package: rhel10/thunderbird-flatpak (Red Hat Enterprise Linux 10) - Affected
Package: thunderbird (Red Hat Enterprise Linux 10) - Affected
Package:
Mozilla
Mozilla Foundation Security Advisory 2026-60: CVE-2026-12309
vendor_mozilla·CVSS 6.5
CVE-2026-12309 [MEDIUM] Mozilla Foundation Security Advisory 2026-60: CVE-2026-12309
Mozilla Foundation Security Advisory 2026-60
CVE: CVE-2026-12309
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 152
Mozilla
Mozilla Foundation Security Advisory 2026-58: CVE-2026-12309
vendor_mozilla·CVSS 6.5
CVE-2026-12309 [MEDIUM] Mozilla Foundation Security Advisory 2026-58: CVE-2026-12309
Mozilla Foundation Security Advisory 2026-58
CVE: CVE-2026-12309
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 140.12
Mozilla
Mozilla Foundation Security Advisory 2026-57: CVE-2026-12309
vendor_mozilla·CVSS 6.5
CVE-2026-12309 [MEDIUM] Mozilla Foundation Security Advisory 2026-57: CVE-2026-12309
Mozilla Foundation Security Advisory 2026-57
CVE: CVE-2026-12309
Product: Firefox
Impact: high
Fixed in: Firefox 152
Mozilla
Mozilla Foundation Security Advisory 2026-61: CVE-2026-12309
vendor_mozilla·CVSS 6.5
CVE-2026-12309 [MEDIUM] Mozilla Foundation Security Advisory 2026-61: CVE-2026-12309
Mozilla Foundation Security Advisory 2026-61
CVE: CVE-2026-12309
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 140.12
VulDB
Mozilla Firefox up to 151 memory corruption (Nessus ID 321490)
vuldb·2026-06-19·CVSS 6.5
CVE-2026-12309 [MEDIUM] Mozilla Firefox up to 151 memory corruption (Nessus ID 321490)
A vulnerability classified as critical has been found in Mozilla Firefox up to 151. Impacted is an unknown function. The manipulation leads to memory corruption.
This vulnerability is documented as CVE-2026-12309. The attack can be initiated remotely. There is not any exploit available.
It is recommended to upgrade the affected component.
GHSA
Memory safety bug fixed in Firefox 152.
ghsa_unreviewed·2026-06-16
CVE-2026-12309 [MEDIUM] CWE-119 Memory safety bug fixed in Firefox 152.
Memory safety bug fixed in Firefox 152. This vulnerability was fixed in Firefox 152 and Firefox ESR 140.12.
No detection rules found.
No public exploits indexed.
2026-06-16
Published