CVE-2026-118021
published 2026-10-27CVE-2026-118021: Sandbox escape due to use-after-free in the XPCOM component. This vulnerability was fixed in Firefox 159 and Thunderbird 159.
PriorityP426
EPSS
0.14%
3.5th percentile
Sandbox escape due to use-after-free in the XPCOM component. This vulnerability was fixed in Firefox 159 and Thunderbird 159.
Affected
3 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| mozilla | firefox | < Firefox 159 | Firefox 159 |
| mozilla | firefox | — | — |
| mozilla | thunderbird | < Thunderbird 159 | Thunderbird 159 |
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GHSA
Sandbox escape due to use-after-free in the XPCOM component.
ghsa_unreviewed·2026-10-27
CVE-2026-118021 Sandbox escape due to use-after-free in the XPCOM component.
Sandbox escape due to use-after-free in the XPCOM component. This vulnerability was fixed in Firefox 159.
Red Hat
firefox: firefox: Sandbox escape via use-after-free in XPCOM
vendor_redhat·2026-10-27
CVE-2026-118021 [HIGH] CWE-825 firefox: firefox: Sandbox escape via use-after-free in XPCOM
firefox: firefox: Sandbox escape via use-after-free in XPCOM
Sandbox escape due to use-after-free in the XPCOM component. This vulnerability was fixed in Firefox 159 and Thunderbird 159.
A flaw was found in Firefox. A use-after-free vulnerability in the Cross-Platform Component Object Model (XPCOM) component allows an attacker to achieve a sandbox escape. An attacker could exploit this memory corruption issue to break out of the browser's restricted security environment (sandbox) and execute arbitrary code on the host system.
Package: firefox (Red Hat Enterprise Linux 10) - Affected
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 2026-118: CVE-2026-118021
vendor_mozilla
CVE-2026-118021 Mozilla Foundation Security Advisory 2026-118: CVE-2026-118021
Mozilla Foundation Security Advisory 2026-118
CVE: CVE-2026-118021
Product: Firefox
Impact: low
Fixed in: Firefox 159
Mozilla
Mozilla Foundation Security Advisory 2026-121: CVE-2026-118021
vendor_mozilla
CVE-2026-118021 Mozilla Foundation Security Advisory 2026-121: CVE-2026-118021
Mozilla Foundation Security Advisory 2026-121
CVE: CVE-2026-118021
Product: Thunderbird
Impact: low
Fixed in: Thunderbird 159
No detection rules found.
No public exploits indexed.
2026-10-27
Published