CVE-2026-74955
published 2026-08-18CVE-2026-74955: Privilege escalation in the Request Handling component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.
PriorityP346high8.8CVSS 3.1
AVNACLPRNUIRSUCHIHAH
EPSS
0.22%
12.5th percentile
Privilege escalation in the Request Handling component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.
Affected
8 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| mozilla | firefox | < Firefox 154 | Firefox 154 |
| mozilla | firefox | < 153.1.0 | 153.1.0 |
| mozilla | firefox | < 154.0.0 | 154.0.0 |
| mozilla | firefox_esr | < Firefox ESR 153.1 | Firefox ESR 153.1 |
| mozilla | thunderbird | < Thunderbird 153.1 | Thunderbird 153.1 |
| mozilla | thunderbird | < Thunderbird 154 | Thunderbird 154 |
| mozilla | thunderbird | < 153.1.0 | 153.1.0 |
| mozilla | thunderbird | < 154.0 | 154.0 |
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: thunderbird: Privilege escalation in the Request Handling component
vendor_redhat·2026-08-18·CVSS 8.8
CVE-2026-74955 [HIGH] CWE-551 firefox: thunderbird: Privilege escalation in the Request Handling component
firefox: thunderbird: Privilege escalation in the Request Handling component
A flaw was found in Firefox and Thunderbird. The Mozilla Foundation's Security Advisory describes the following issue:
Privilege escalation in the Request Handling 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) - Not affected
Package: rhel10/firefox-flatpak (Red Hat Enterprise Linux 10) - Not affected
Package: firefox (Red Hat Enterprise Linux 6) - Not affected
Package: firefox (Red Hat Enterprise Linux 7) - Not affected
Package: firefox (Red Hat Enterprise Linux 8) - Not affected
Package: firefox (Red Hat Enterprise Linux 9) - Not affected
Mozilla
Mozilla Foundation Security Advisory 2026-74: CVE-2026-74955
vendor_mozilla
CVE-2026-74955 Mozilla Foundation Security Advisory 2026-74: CVE-2026-74955
Mozilla Foundation Security Advisory 2026-74
CVE: CVE-2026-74955
Product: Firefox
Impact: high
Fixed in: Firefox 154
Mozilla
Mozilla Foundation Security Advisory 2026-80: CVE-2026-74955
vendor_mozilla
CVE-2026-74955 Mozilla Foundation Security Advisory 2026-80: CVE-2026-74955
Mozilla Foundation Security Advisory 2026-80
CVE: CVE-2026-74955
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 153.1
Mozilla
Mozilla Foundation Security Advisory 2026-77: CVE-2026-74955
vendor_mozilla
CVE-2026-74955 Mozilla Foundation Security Advisory 2026-77: CVE-2026-74955
Mozilla Foundation Security Advisory 2026-77
CVE: CVE-2026-74955
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 153.1
Mozilla
Mozilla Foundation Security Advisory 2026-78: CVE-2026-74955
vendor_mozilla
CVE-2026-74955 Mozilla Foundation Security Advisory 2026-78: CVE-2026-74955
Mozilla Foundation Security Advisory 2026-78
CVE: CVE-2026-74955
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 154
GHSA
Privilege escalation in the Request Handling component.
ghsa_unreviewed·2026-08-18
CVE-2026-74955 [HIGH] CWE-269 Privilege escalation in the Request Handling component.
Privilege escalation in the Request Handling component. This vulnerability was fixed in Firefox 154 and Firefox ESR 153.1.
No detection rules found.
No public exploits indexed.
2026-08-18
Published