CVE-2026-84145
published 2026-09-01CVE-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…
PriorityP342high7.5CVSS 3.1
AVNACHPRNUIRSUCHIHAH
EPSS
0.37%
30.4th percentile
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.
Affected
18 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| mozilla | firefox | < Firefox 155 | Firefox 155 |
| mozilla | firefox | < 115.40.0 | 115.40.0 |
| mozilla | firefox | — | — |
| mozilla | firefox | >= 116.0 < 140.15.0 | 140.15.0 |
| mozilla | firefox | >= 141.0.0 < 153.2.0 | 153.2.0 |
| mozilla | firefox | >= 154.0.0 < 155.0.0 | 155.0.0 |
| mozilla | firefox_esr | < Firefox ESR 153.2 | Firefox ESR 153.2 |
| mozilla | firefox_esr | < Firefox ESR 115.40 | Firefox ESR 115.40 |
| mozilla | firefox_esr | < Firefox ESR 140.15 | Firefox ESR 140.15 |
| mozilla | thunderbird | < Thunderbird 155 | Thunderbird 155 |
| mozilla | thunderbird | < Thunderbird 153.2 | Thunderbird 153.2 |
| mozilla | thunderbird | < Thunderbird 140.15 | Thunderbird 140.15 |
| mozilla | thunderbird | < 140.15.0 | 140.15.0 |
| mozilla | thunderbird | — | — |
| mozilla | thunderbird | >= 141.0 < 153.2.0 | 153.2.0 |
| mozilla | thunderbird | >= 154.0 < 155.0 | 155.0 |
| rhel10 | firefox-flatpak | — | — |
| rhel10 | thunderbird-flatpak | — | — |
CVSS provenance
nvdv3.17.5HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
vendor_redhat7.5HIGH
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Red Hat
firefox: Internally found bugs fixed in Firefox 155, Firefox ESR 153.2, Firefox ESR 140.15 and Firefox ESR 115.40
vendor_redhat·2026-09-01·CVSS 7.5
CVE-2026-84145 [HIGH] CWE-825 firefox: Internally found bugs fixed in Firefox 155, Firefox ESR 153.2, Firefox ESR 140.15 and Firefox ESR 115.40
firefox: Internally found bugs fixed in Firefox 155, Firefox ESR 153.2, Firefox ESR 140.15 and Firefox ESR 115.40
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.
A flaw was found in Firefox. The Mozilla Foundation's Security Advisory describes the following issue:
Internally found bugs present in Firefox 154, Firefox ESR 153.1, Firefox ESR 140.14 and Firefox ESR 115.39. Some of these bugs showed evidence of
Mozilla
Mozilla Foundation Security Advisory 2026-86: CVE-2026-84145
vendor_mozilla·CVSS 7.5
CVE-2026-84145 [HIGH] Mozilla Foundation Security Advisory 2026-86: CVE-2026-84145
Mozilla Foundation Security Advisory 2026-86
CVE: CVE-2026-84145
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 155
Mozilla
Mozilla Foundation Security Advisory 2026-82: CVE-2026-84145
vendor_mozilla·CVSS 7.5
CVE-2026-84145 [HIGH] Mozilla Foundation Security Advisory 2026-82: CVE-2026-84145
Mozilla Foundation Security Advisory 2026-82
CVE: CVE-2026-84145
Product: Firefox
Impact: high
Fixed in: Firefox 155
Mozilla
Mozilla Foundation Security Advisory 2026-88: CVE-2026-84145
vendor_mozilla·CVSS 7.5
CVE-2026-84145 [HIGH] Mozilla Foundation Security Advisory 2026-88: CVE-2026-84145
Mozilla Foundation Security Advisory 2026-88
CVE: CVE-2026-84145
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 153.2
Mozilla
Mozilla Foundation Security Advisory 2026-87: CVE-2026-84145
vendor_mozilla·CVSS 7.5
CVE-2026-84145 [HIGH] Mozilla Foundation Security Advisory 2026-87: CVE-2026-84145
Mozilla Foundation Security Advisory 2026-87
CVE: CVE-2026-84145
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 140.15
Mozilla
Mozilla Foundation Security Advisory 2026-85: CVE-2026-84145
vendor_mozilla·CVSS 7.5
CVE-2026-84145 [HIGH] Mozilla Foundation Security Advisory 2026-85: CVE-2026-84145
Mozilla Foundation Security Advisory 2026-85
CVE: CVE-2026-84145
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 153.2
Mozilla
Mozilla Foundation Security Advisory 2026-83: CVE-2026-84145
vendor_mozilla·CVSS 7.5
CVE-2026-84145 [HIGH] Mozilla Foundation Security Advisory 2026-83: CVE-2026-84145
Mozilla Foundation Security Advisory 2026-83
CVE: CVE-2026-84145
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 115.40
Mozilla
Mozilla Foundation Security Advisory 2026-84: CVE-2026-84145
vendor_mozilla·CVSS 7.5
CVE-2026-84145 [HIGH] Mozilla Foundation Security Advisory 2026-84: CVE-2026-84145
Mozilla Foundation Security Advisory 2026-84
CVE: CVE-2026-84145
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 140.15
VulDB
Mozilla Firefox up to 115.39/140.14/153.1/154 memory corruption (Nessus ID 342302)
vuldb·2026-09-03·CVSS 7.5
CVE-2026-84145 [HIGH] Mozilla Firefox up to 115.39/140.14/153.1/154 memory corruption (Nessus ID 342302)
A vulnerability has been found in Mozilla Firefox up to 115.39/140.14/153.1/154 and classified as critical. Affected by this vulnerability is an unknown functionality. Performing a manipulation results in memory corruption.
This vulnerability is reported as CVE-2026-84145. The attack is possible to be carried out remotely. No exploit exists.
The affected component should be upgraded.
GHSA
Internally found bugs present in Firefox 154, Firefox ESR 153.1, Firefox ESR 140.14 and Firefox ESR 115.39.
ghsa_unreviewed·2026-09-01
CVE-2026-84145 [HIGH] CWE-119 Internally found bugs present in Firefox 154, Firefox ESR 153.1, Firefox ESR 140.14 and Firefox ESR 115.39.
Internally found bugs present in Firefox 154, Firefox ESR 153.1, Firefox ESR 140.14 and Firefox ESR 115.39. 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, and Firefox ESR 153.2.
No detection rules found.
No public exploits indexed.
https://bugzilla.mozilla.org/buglist.cgi?bug_id=2054640%2C2054650%2C2054652%2C2055693%2C2055705%2C2058051%2C2058652%2C2058660%2C2059027%2C2061220%2C2061242%2C2061285%2C2061300%2C2061316%2C2061397https://bugzilla.mozilla.org/buglist.cgi?bug_id=2058001%2C2059139%2C2062400%2C2062419https://bugzilla.mozilla.org/show_bug.cgi?id=2055678https://www.mozilla.org/security/advisories/mfsa2026-82/https://www.mozilla.org/security/advisories/mfsa2026-83/https://www.mozilla.org/security/advisories/mfsa2026-84/https://www.mozilla.org/security/advisories/mfsa2026-85/https://www.mozilla.org/security/advisories/mfsa2026-86/https://www.mozilla.org/security/advisories/mfsa2026-87/https://www.mozilla.org/security/advisories/mfsa2026-88/
2026-09-01
Published