CVE-2026-92015
published 2026-09-15CVE-2026-92015: Privilege escalation in the WebExtensions component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3…
PriorityP346high8.8CVSS 3.1
AVNACLPRNUIRSUCHIHAH
EPSS
0.26%
16.5th percentile
Privilege escalation in the WebExtensions component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
Affected
18 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| mozilla | firefox | < Firefox 156 | Firefox 156 |
| mozilla | firefox | < 115.41.0 | 115.41.0 |
| mozilla | firefox | — | — |
| mozilla | firefox | >= 116.0 < 140.16.0 | 140.16.0 |
| mozilla | firefox | >= 141.0 < 153.3.0 | 153.3.0 |
| mozilla | firefox | >= 154.0.0 < 156.0.0 | 156.0.0 |
| mozilla | firefox_esr | < Firefox ESR 153.3 | Firefox ESR 153.3 |
| mozilla | firefox_esr | < Firefox ESR 115.41 | Firefox ESR 115.41 |
| mozilla | firefox_esr | < Firefox ESR 140.16 | Firefox ESR 140.16 |
| mozilla | thunderbird | < Thunderbird 140.16 | Thunderbird 140.16 |
| mozilla | thunderbird | < Thunderbird 156 | Thunderbird 156 |
| mozilla | thunderbird | < Thunderbird 153.3 | Thunderbird 153.3 |
| mozilla | thunderbird | < 140.16.0 | 140.16.0 |
| mozilla | thunderbird | — | — |
| mozilla | thunderbird | >= 141.0 < 153.3.0 | 153.3.0 |
| mozilla | thunderbird | >= 154.0 < 156.0 | 156.0 |
| rhel10 | firefox-flatpak | — | — |
| rhel10 | thunderbird-flatpak | — | — |
CVSS provenance
nvdv3.18.8HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
vendor_redhat8.8HIGH
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VulDB
Mozilla Firefox up to 115.40/140.15/153.2/155 WebExtensions privileges management (EUVD-2026-78478 / WID-SEC-2026-3375)
vuldb·2026-09-22·CVSS 8.8
CVE-2026-92015 [HIGH] Mozilla Firefox up to 115.40/140.15/153.2/155 WebExtensions privileges management (EUVD-2026-78478 / WID-SEC-2026-3375)
A vulnerability, which was classified as critical, has been found in Mozilla Firefox up to 115.40/140.15/153.2/155. Impacted is an unknown function of the component WebExtensions. This manipulation causes improper privilege management.
This vulnerability is tracked as CVE-2026-92015. The attack is possible to be carried out remotely. No exploit exists.
It is advisable to upgrade the affected component.
GHSA
Privilege escalation in the WebExtensions component.
ghsa_unreviewed·2026-09-15
CVE-2026-92015 [HIGH] CWE-269 Privilege escalation in the WebExtensions component.
Privilege escalation in the WebExtensions component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, and Firefox ESR 153.3.
Red Hat
firefox: thunderbird: Privilege escalation in the WebExtensions component
vendor_redhat·2026-09-15·CVSS 8.8
CVE-2026-92015 [HIGH] CWE-266 firefox: thunderbird: Privilege escalation in the WebExtensions component
firefox: thunderbird: Privilege escalation in the WebExtensions component
Privilege escalation in the WebExtensions component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.
A flaw was found in Firefox and Thunderbird. The Mozilla Foundation's Security Advisory describes the following issue:
Privilege escalation in the WebExtensions component
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) - Affect
Mozilla
Mozilla Foundation Security Advisory 2026-90: CVE-2026-92015
vendor_mozilla·CVSS 8.8
CVE-2026-92015 [HIGH] Mozilla Foundation Security Advisory 2026-90: CVE-2026-92015
Mozilla Foundation Security Advisory 2026-90
CVE: CVE-2026-92015
Product: Firefox
Impact: low
Fixed in: Firefox 156
Mozilla
Mozilla Foundation Security Advisory 2026-93: CVE-2026-92015
vendor_mozilla·CVSS 8.8
CVE-2026-92015 [HIGH] Mozilla Foundation Security Advisory 2026-93: CVE-2026-92015
Mozilla Foundation Security Advisory 2026-93
CVE: CVE-2026-92015
Product: Firefox ESR
Impact: low
Fixed in: Firefox ESR 153.3
Mozilla
Mozilla Foundation Security Advisory 2026-95: CVE-2026-92015
vendor_mozilla·CVSS 8.8
CVE-2026-92015 [HIGH] Mozilla Foundation Security Advisory 2026-95: CVE-2026-92015
Mozilla Foundation Security Advisory 2026-95
CVE: CVE-2026-92015
Product: Thunderbird
Impact: moderate
Fixed in: Thunderbird 140.16
Mozilla
Mozilla Foundation Security Advisory 2026-94: CVE-2026-92015
vendor_mozilla·CVSS 8.8
CVE-2026-92015 [HIGH] Mozilla Foundation Security Advisory 2026-94: CVE-2026-92015
Mozilla Foundation Security Advisory 2026-94
CVE: CVE-2026-92015
Product: Thunderbird
Impact: low
Fixed in: Thunderbird 156
Mozilla
Mozilla Foundation Security Advisory 2026-96: CVE-2026-92015
vendor_mozilla·CVSS 8.8
CVE-2026-92015 [HIGH] Mozilla Foundation Security Advisory 2026-96: CVE-2026-92015
Mozilla Foundation Security Advisory 2026-96
CVE: CVE-2026-92015
Product: Thunderbird
Impact: low
Fixed in: Thunderbird 153.3
Mozilla
Mozilla Foundation Security Advisory 2026-91: CVE-2026-92015
vendor_mozilla·CVSS 8.8
CVE-2026-92015 [HIGH] Mozilla Foundation Security Advisory 2026-91: CVE-2026-92015
Mozilla Foundation Security Advisory 2026-91
CVE: CVE-2026-92015
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 115.41
Mozilla
Mozilla Foundation Security Advisory 2026-92: CVE-2026-92015
vendor_mozilla·CVSS 8.8
CVE-2026-92015 [HIGH] Mozilla Foundation Security Advisory 2026-92: CVE-2026-92015
Mozilla Foundation Security Advisory 2026-92
CVE: CVE-2026-92015
Product: Firefox ESR
Impact: moderate
Fixed in: Firefox ESR 140.16
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2026-92015 firefox: thunderbird: Privilege escalation in the WebExtensions component
bugzilla·2026-09-15·CVSS 8.8
CVE-2026-92015 [HIGH] CVE-2026-92015 firefox: thunderbird: Privilege escalation in the WebExtensions component
CVE-2026-92015 firefox: thunderbird: Privilege escalation in the WebExtensions component
Privilege escalation in the WebExtensions component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, and Firefox ESR 153.3.
Hackernews
⚡ Weekly Recap: Cisco 0-Day, AI Agent RCE, ClickFix Attacks, ClickFix Surge, and Browser Hijacks
blogs_hackernews·2026-09-21·CVSS 10.0
CVE-2026-76460 [CRITICAL] ⚡ Weekly Recap: Cisco 0-Day, AI Agent RCE, ClickFix Attacks, ClickFix Surge, and Browser Hijacks
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## ⚡ Weekly Recap: Cisco 0-Day, AI Agent RCE, ClickFix Attacks, ClickFix Surge, and Browser Hijacks
A browser. A plugin. A package. A login screen. Normal stuff. That is basically the problem this week.
The trouble keeps showing up inside things people already trust: code that takes a bad turn, old payloads coming back, exposed systems, weak checks, fake fixes, and attack paths that look almost too easy. Even the research side is getting messy, with more findings, more automation, and not always more clarity.
Nothing here needs much drama. Just a lot of small doors left open. Here’s what happened.
## ⚡ Threat of the Week
C
https://bugzilla.mozilla.org/show_bug.cgi?id=2060235https://www.mozilla.org/security/advisories/mfsa2026-90/https://www.mozilla.org/security/advisories/mfsa2026-91/https://www.mozilla.org/security/advisories/mfsa2026-92/https://www.mozilla.org/security/advisories/mfsa2026-93/https://www.mozilla.org/security/advisories/mfsa2026-94/https://www.mozilla.org/security/advisories/mfsa2026-95/https://www.mozilla.org/security/advisories/mfsa2026-96/
2026-09-15
Published