Patchfirst
CVE-2026-109708 Critical · 9.6 EPSS 0.3%

Sandbox escape due to incorrect boundary conditions in the Networking component

Mozilla · Firefox

Summary

A sandbox escape caused by incorrect boundary conditions in the Networking component of Mozilla Firefox allows code to break out of the browser's sandbox. An attacker can exploit it remotely without authentication, but it requires the user to take an action such as visiting a malicious page or opening crafted content.

Official description · NVD

Sandbox escape due to incorrect boundary conditions 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
14.4 / 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
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