CVE-2026-8957
published 2026-05-19CVE-2026-8957: Privilege escalation in the Enterprise Policies component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird…
PriorityP347high8.8CVSS 3.1
AVNACLPRNUIRSUCHIHAH
EPSS
0.39%
32.4th percentile
Privilege escalation in the Enterprise Policies component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
Affected
10 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| mozilla | firefox | < Firefox 151 | Firefox 151 |
| mozilla | firefox | < 140.11.0 | 140.11.0 |
| mozilla | firefox | < 151.0.0 | 151.0.0 |
| mozilla | firefox | — | — |
| mozilla | firefox_esr | < Firefox ESR 140.11 | Firefox ESR 140.11 |
| mozilla | thunderbird | < Thunderbird 140.11 | Thunderbird 140.11 |
| mozilla | thunderbird | < Thunderbird 151 | Thunderbird 151 |
| mozilla | thunderbird | < 140.11 | 140.11 |
| mozilla | thunderbird | < 151.0.0 | 151.0.0 |
| rhel10 | firefox-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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Red Hat
firefox: Privilege escalation in the Enterprise Policies component
vendor_redhat·2026-05-19·CVSS 8.8
CVE-2026-8957 [HIGH] CWE-266 firefox: Privilege escalation in the Enterprise Policies component
firefox: Privilege escalation in the Enterprise Policies component
A flaw was found in Firefox. The Mozilla Foundation's Security Advisory describes the following issue:
Privilege escalation in the Enterprise Policies 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: firefox (Red Hat Enterprise Linux 6) - Out of support scope
Package: firefox (Red Hat Enterprise Linux 7) - Affected
Package: firefox (Red Hat Enterprise Linux 8) - Affected
Package: firefox (Red Hat Enterprise Linux 9) - Affected
Mozilla
Mozilla Foundation Security Advisory 2026-46: CVE-2026-8957
vendor_mozilla·CVSS 6.5
CVE-2026-8957 [MEDIUM] Mozilla Foundation Security Advisory 2026-46: CVE-2026-8957
Mozilla Foundation Security Advisory 2026-46
CVE: CVE-2026-8957
Product: Firefox
Impact: high
Fixed in: Firefox 151
Mozilla
Mozilla Foundation Security Advisory 2026-48: CVE-2026-8957
vendor_mozilla·CVSS 6.5
CVE-2026-8957 [MEDIUM] Mozilla Foundation Security Advisory 2026-48: CVE-2026-8957
Mozilla Foundation Security Advisory 2026-48
CVE: CVE-2026-8957
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 140.11
Mozilla
Mozilla Foundation Security Advisory 2026-51: CVE-2026-8957
vendor_mozilla·CVSS 6.5
CVE-2026-8957 [MEDIUM] Mozilla Foundation Security Advisory 2026-51: CVE-2026-8957
Mozilla Foundation Security Advisory 2026-51
CVE: CVE-2026-8957
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 140.11
Mozilla
Mozilla Foundation Security Advisory 2026-50: CVE-2026-8957
vendor_mozilla·CVSS 6.5
CVE-2026-8957 [MEDIUM] Mozilla Foundation Security Advisory 2026-50: CVE-2026-8957
Mozilla Foundation Security Advisory 2026-50
CVE: CVE-2026-8957
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 151
VulDB
Mozilla Firefox up to 140.10/150 Enterprise Policies privilege escalation (EUVD-2026-30908)
vuldb·2026-05-19·CVSS 6.5
CVE-2026-8957 [MEDIUM] Mozilla Firefox up to 140.10/150 Enterprise Policies privilege escalation (EUVD-2026-30908)
A vulnerability was found in Mozilla Firefox up to 140.10/150. It has been classified as problematic. Impacted is an unknown function of the component Enterprise Policies. Performing a manipulation results in privilege escalation.
This vulnerability is reported as CVE-2026-8957. The attacker must have access to the local network to execute the attack. No exploit exists.
Upgrading the affected component is recommended.
GHSA
GHSA-83v4-m9qr-xgp9: Privilege escalation in the Enterprise Policies component
ghsa_unreviewed·2026-05-19
CVE-2026-8957 [MEDIUM] CWE-269 GHSA-83v4-m9qr-xgp9: Privilege escalation in the Enterprise Policies component
Privilege escalation in the Enterprise Policies component. This vulnerability was fixed in Firefox 151 and Firefox ESR 140.11.
No detection rules found.
No public exploits indexed.
Bugzilla
Enterprise Policy WebsiteFilter block bypassed by trailing-dot FQDN in Firefox
bugzilla·2026-06-03
CVE-2026-8957 Enterprise Policy WebsiteFilter block bypassed by trailing-dot FQDN in Firefox
Enterprise Policy WebsiteFilter block bypassed by trailing-dot FQDN in Firefox
- Affected: Firefox with Enterprise Policies enabled — `WebsiteFilter` `Block` enforcement. Confirmed: Nightly 153.0a1 + mozilla-central HEAD 5836a06272 (static analysis + local runtime). Likely but not independently tested: other release/beta/ESR channels sharing the same `WebsiteFilter.sys.mjs` → `MatchPatternSet` → `MatchesDomain(aURL.Host())` path.
- Severity: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N (4.3 Medium)
- CVE: not-requested
- CWE: CWE-1289 (Improper Validation of Unsafe Equivalence in Input), CWE-863 (Incorrect Authorization)
## Overview
The `WebsiteFilter` enterprise policy lets an administrator block navigation to a list of sites (`Block: ["*://example.org/*", ...]`). The block decision ma
Bugzilla
CVE-2026-8957 firefox: Privilege escalation in the Enterprise Policies component
bugzilla·2026-05-19·CVSS 8.8
CVE-2026-8957 [HIGH] CVE-2026-8957 firefox: Privilege escalation in the Enterprise Policies component
CVE-2026-8957 firefox: Privilege escalation in the Enterprise Policies component
Privilege escalation in the Enterprise Policies component. This vulnerability was fixed in Firefox 151 and Firefox ESR 140.11.
2026-05-19
Published