CVE-2026-74989
published 2026-08-18CVE-2026-74989: Internally found bugs present in Thunderbird 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume…
PriorityP348critical9.8CVSS 3.1
AVNACLPRNUINSUCHIHAH
EPSS
0.57%
45.6th percentile
Internally found bugs present in Thunderbird 153. 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 154 and Thunderbird 154.
Affected
4 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| mozilla | firefox | < Firefox 154 | Firefox 154 |
| mozilla | firefox | < 154.0.0 | 154.0.0 |
| mozilla | thunderbird | < Thunderbird 154 | Thunderbird 154 |
| mozilla | thunderbird | < 154.0 | 154.0 |
CVSS provenance
nvdv3.19.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
vendor_redhat9.8CRITICAL
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Red Hat
firefox: Internally found bugs fixed in Firefox 154
vendor_redhat·2026-08-18·CVSS 9.8
CVE-2026-74989 [CRITICAL] CWE-825 firefox: Internally found bugs fixed in Firefox 154
firefox: Internally found bugs fixed in Firefox 154
Internally found bugs present in Thunderbird 153. 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 154 and Thunderbird 154.
A flaw was found in Firefox. The Mozilla Foundation's Security Advisory describes the following issue:
Internally found bugs present in Firefox 153. 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.
Statement: Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory.
Package:
Mozilla
Mozilla Foundation Security Advisory 2026-74: CVE-2026-74989
vendor_mozilla
CVE-2026-74989 Mozilla Foundation Security Advisory 2026-74: CVE-2026-74989
Mozilla Foundation Security Advisory 2026-74
CVE: CVE-2026-74989
Product: Firefox
Impact: high
Fixed in: Firefox 154
Mozilla
Mozilla Foundation Security Advisory 2026-78: CVE-2026-74989
vendor_mozilla
CVE-2026-74989 Mozilla Foundation Security Advisory 2026-78: CVE-2026-74989
Mozilla Foundation Security Advisory 2026-78
CVE: CVE-2026-74989
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 154
GHSA
Internally found bugs present in Firefox 153.
ghsa_unreviewed·2026-08-18
CVE-2026-74989 Internally found bugs present in Firefox 153.
Internally found bugs present in Firefox 153. 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 154.
No detection rules found.
No public exploits indexed.
https://bugzilla.mozilla.org/buglist.cgi?bug_id=2022257%2C2027351%2C2027380%2C2029289https://bugzilla.mozilla.org/buglist.cgi?bug_id=2027388%2C2029750%2C2029794%2C2043298%2C2045126%2C2049810%2C2051741https://www.mozilla.org/security/advisories/mfsa2026-74/https://www.mozilla.org/security/advisories/mfsa2026-78/
2026-08-18
Published