CVE-2026-92040
HIGH 8.8 ALL-YEARSUse-after-free in the JavaScript: WebAssembly component. This vulnerability was fixed in Firefox 156 and Thunderbird 156.
ELEVATED IMPACT
Severe if exploited (CVSS 8.8), but no confirmed exploitation. Patch on a normal cadence.
Exploitation likelihood
0.4%chance of exploitation in 30 days · 35th percentile
○ In CISA KEV○ Public exploit / PoC◆ SSVC: exploitation none, automatable no
Impact if exploited
8.8CVSS 3.1 · HIGH · ADP
- ConfidentialityHigh
- IntegrityHigh
- AvailabilityHigh
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ✓Privileges: No account or privileges required
- ⚠User interaction: A user must take an action (click / open a file)
- ✓Complexity: No special conditions — reliably repeatable
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept & exploit code
No public exploit or proof-of-concept code is catalogued for this CVE (no ExploitDB, Nuclei, or CISA-KEV entry). It may still exist — search GitHub or check the references below.
Weakness (CWE)
- CWE-416: Use After Free
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Known Affected Software Configurations
| Vendor | Product | Version range |
|---|---|---|
| Mozilla | Firefox | < 156.0.0 |
| Mozilla | Thunderbird | < 156.0 |
All CVSS metrics
- HIGH 8.8 v3.1 · ADP Primary
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - HIGH 8.8 v3.1 · NVD Secondary
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H