CVE-2026-6763
published 2026-04-21CVE-2026-6763: Mitigation bypass in the File Handling component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
PriorityP335medium6.5CVSS 3.1
AVNACLPRNUINSUCLILAN
EPSS
0.19%
8.9th percentile
Mitigation bypass in the File Handling component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
Affected
9 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| mozilla | firefox | < Firefox 150 | Firefox 150 |
| mozilla | firefox | < 140.10.0 | 140.10.0 |
| mozilla | firefox | < 150.0 | 150.0 |
| mozilla | firefox | — | — |
| mozilla | firefox_esr | < Firefox ESR 140.10 | Firefox ESR 140.10 |
| mozilla | thunderbird | < Thunderbird 150 | Thunderbird 150 |
| mozilla | thunderbird | < Thunderbird 140.10 | Thunderbird 140.10 |
| mozilla | thunderbird | >= 140.0 < 140.10.0 | 140.10.0 |
| rhel10 | firefox-flatpak | — | — |
CVSS provenance
nvdv3.16.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
vendor_redhat6.5MEDIUM
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Red Hat
firefox: Mitigation bypass in the File Handling component
vendor_redhat·2026-04-21·CVSS 6.5
CVE-2026-6763 [MEDIUM] CWE-66 firefox: Mitigation bypass in the File Handling component
firefox: Mitigation bypass in the File Handling component
A flaw was found in Firefox. The Mozilla Foundation's Security Advisory describes the following issue:
Mitigation bypass in the File 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) - 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 2026-33: CVE-2026-6763
vendor_mozilla·CVSS 6.5
CVE-2026-6763 [MEDIUM] Mozilla Foundation Security Advisory 2026-33: CVE-2026-6763
Mozilla Foundation Security Advisory 2026-33
CVE: CVE-2026-6763
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 150
Mozilla
Mozilla Foundation Security Advisory 2026-32: CVE-2026-6763
vendor_mozilla·CVSS 6.5
CVE-2026-6763 [MEDIUM] Mozilla Foundation Security Advisory 2026-32: CVE-2026-6763
Mozilla Foundation Security Advisory 2026-32
CVE: CVE-2026-6763
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 140.10
Mozilla
Mozilla Foundation Security Advisory 2026-30: CVE-2026-6763
vendor_mozilla·CVSS 6.5
CVE-2026-6763 [MEDIUM] Mozilla Foundation Security Advisory 2026-30: CVE-2026-6763
Mozilla Foundation Security Advisory 2026-30
CVE: CVE-2026-6763
Product: Firefox
Impact: high
Fixed in: Firefox 150
Mozilla
Mozilla Foundation Security Advisory 2026-34: CVE-2026-6763
vendor_mozilla·CVSS 6.5
CVE-2026-6763 [MEDIUM] Mozilla Foundation Security Advisory 2026-34: CVE-2026-6763
Mozilla Foundation Security Advisory 2026-34
CVE: CVE-2026-6763
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 140.10
VulDB
Mozilla Firefox up to 149 File Remote Code Execution (Nessus ID 310350)
vuldb·2026-04-26·CVSS 6.5
CVE-2026-6763 [MEDIUM] Mozilla Firefox up to 149 File Remote Code Execution (Nessus ID 310350)
A vulnerability classified as critical has been found in Mozilla Firefox up to 149. The affected element is an unknown function of the component File Handler. This manipulation causes Remote Code Execution.
This vulnerability is handled as CVE-2026-6763. The attack can be initiated remotely. There is not any exploit available.
It is recommended to upgrade the affected component.
GHSA
GHSA-jgph-c6j5-5mm2: Mitigation bypass in the File Handling component
ghsa_unreviewed·2026-04-21
CVE-2026-6763 [MEDIUM] CWE-693 GHSA-jgph-c6j5-5mm2: Mitigation bypass in the File Handling component
Mitigation bypass in the File Handling component. This vulnerability was fixed in Firefox 150 and Firefox ESR 140.10.
No detection rules found.
No public exploits indexed.
2026-04-21
Published