CVE-2026-4698 is a critical JIT miscompilation vulnerability within the JavaScript Engine component of Mozilla Firefox and Thunderbird, affecting multiple versions including Firefox < 149 and Thunderbird < 149. Rated 9.8 Critical (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), it allows unauthenticated remote attackers to achieve complete system compromise with high confidentiality, integrity, and availability impacts, requiring no user interaction. While there is no evidence of active exploitation or public exploit code available, the vulnerability has generated some community discussion and media coverage, indicating awareness.
| Vendor | Product | Version(s) | CPE |
|---|---|---|---|
< 115.34.0CPE matchmatch criteria | cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:* | ||
< 149.0CPE matchmatch criteria | cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:* | ||
>= 128.0, < 140.9.0CPE matchmatch criteria | cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:* |
CVSS version used by this source: 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.
The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.