Patchfirst
CVE-2026-109745 Critical · 9.6 EPSS 0.3%

Sandbox escape due to uninitialized memory in the DOM: Web Serial component

Mozilla · Firefox

Summary

The flaw is an uninitialized-memory bug in the DOM: Web Serial component of Mozilla Firefox, which allows a sandbox escape. An attacker who can get a user to interact with malicious web content can exploit it over the network without authentication to break out of the browser sandbox, with the attack vector indicating user interaction is required and no privileges are needed.

Official description · NVD

Sandbox escape due to uninitialized memory in the DOM: Web Serial component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.

Breakdown
14.7 / 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

5 links, grouped by NVD tag
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