Vulnerability · Published May 12, 2026 · Assigned by mozilla
CVE-2026-8390Use-after-free in the JavaScript: WebAssembly component
High 7.3
In plain English
A high-severity use-after-free 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 0.5% (higher than 43% of all known vulnerabilities).
Severity (CVSS 3.1)7.3High
Exploit odds (30 days)0.5%top 57.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Use-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 150.0.3.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu:22.04:LTS | mozjs102 | no fix listed | UBUNTU-CVE-2026-8390 |
| Ubuntu:24.04:LTS | mozjs102 | no fix listed | UBUNTU-CVE-2026-8390 |
| Ubuntu:24.04:LTS | mozjs115 | no fix listed | UBUNTU-CVE-2026-8390 |
| Ubuntu:22.04:LTS | mozjs78 | no fix listed | UBUNTU-CVE-2026-8390 |
| Ubuntu:22.04:LTS | mozjs91 | no fix listed | UBUNTU-CVE-2026-8390 |
| Ubuntu:22.04:LTS | thunderbird | no fix listed | UBUNTU-CVE-2026-8390 |
Affected products (as reported)
Weakness: CWE-416, CWE-825 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2038081
- https://www.mozilla.org/security/advisories/mfsa2026-45/
- https://access.redhat.com/security/cve/CVE-2026-8390 vdb-entry, x_refsource_REDHAT
- RHBZ#2476474 issue-tracking, x_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-8390.json x_sadp-csaf-vex