Patchfirst
CVE-2026-109707 Critical · 9.6 EPSS 0.3%

Sandbox escape due to use-after-free in the Networking component

Mozilla · Firefox

Summary

A use-after-free flaw in the Networking component of Mozilla Firefox allows a sandbox escape, meaning code running inside the browser's sandbox can break out of its restrictions. An attacker would need to lure a user into interacting with malicious content, such as visiting a crafted page, and can reach the vulnerable code over the network without authentication.

Official description · NVD

Sandbox escape due to use-after-free in the Networking component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, Thunderbird 153.5, and Firefox ESR 115.44.

Breakdown
14.1 / 100
Exploited
Not confirmed
Reports
0
Tactics
0/15

Disclosed on 13 Oct 2026. No public exploit code or confirmed exploitation is recorded.

techniques

No techniques linked

No ATT&CK techniques are linked to this CVE yet. MITRE CTID has not mapped it, and no report passage in the corpus ties it to a technique.

What security researchers reported

Not named in any threat report yet

Also mentioned in 9 community threat pulses (AlienVault OTX)

Weaker evidence

Pulses are indicator collections that anyone can publish. A mention is not confirmation of exploitation.

References

6 links, grouped by NVD tag
↑ ↓ chooseEnter openEsc close