Vulnerability · Published Feb 24, 2026 · Assigned by mozilla
CVE-2026-2796JIT miscompilation in the JavaScript: WebAssembly component
Critical 9.8
In plain English
A critical-severity type confusion in Firefox from Mozilla. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.9% (higher than 61% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code.
Severity (CVSS 3.1)9.8Critical
Exploit odds (30 days)0.9%top 38.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack tooling1Public PoC
Official description
JIT miscompilation in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 148 and Thunderbird 148.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu:22.04:LTS | mozjs102 | no fix listed | UBUNTU-CVE-2026-2796 |
| Ubuntu:24.04:LTS | mozjs102 | no fix listed | UBUNTU-CVE-2026-2796 |
| Ubuntu:24.04:LTS | mozjs115 | no fix listed | UBUNTU-CVE-2026-2796 |
| Ubuntu:22.04:LTS | mozjs78 | no fix listed | UBUNTU-CVE-2026-2796 |
| Ubuntu:22.04:LTS | mozjs91 | no fix listed | UBUNTU-CVE-2026-2796 |
| Ubuntu:22.04:LTS | thunderbird | no fix listed | UBUNTU-CVE-2026-2796 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox | see references |
| Mozilla | Thunderbird | see references |
Weakness: CWE-843 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2013165
- https://www.mozilla.org/security/advisories/mfsa2026-13/
- https://www.mozilla.org/security/advisories/mfsa2026-16/
- https://access.redhat.com/security/cve/CVE-2026-2796 vdb-entry, x_refsource_REDHAT
- RHBZ#2442301 issue-tracking, x_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-2796.json x_sadp-csaf-vex