Sandbox escape, site isolation issue due to incorrect boundary conditions, use-after-free in the Networking component
Mozilla · Firefox
Firefox contains a use-after-free flaw in its Networking component, stemming from incorrect boundary conditions in site isolation that allow a sandbox escape. An attacker who can get a user to interact with malicious content, with no prior authentication and over the network, can break out of the browser's sandbox.
Sandbox escape, site isolation issue due to incorrect boundary conditions, 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.
- Exploited
- Not confirmed
- Reports
- 0
- Tactics
- 0/15
Exploitation timelineDated milestones for a CVE: when it was disclosed, when exploit code became public, when exploitation was confirmed, and when threat reports named it.
Disclosed on 13 Oct 2026. No public exploit code or confirmed exploitation is recorded.
MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. techniques
No techniques linkedNo 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 yetAlso mentioned in 9 community threat pulses (AlienVault OTX)
Weaker evidencePulses are indicator collections that anyone can publish. A mention is not confirmation of exploitation.
- Known_Cve | Oct 22, 2026 | Part 1/421 Oct 2026
- Known_Cve | Oct 21, 2026 | Part 2/420 Oct 2026
- Known_Cve | Oct 20, 2026 | Part 2/419 Oct 2026
- Known_Cve | Oct 19, 2026 | Part 2/418 Oct 2026
- Known_Cve | Oct 18, 2026 | Part 2/417 Oct 2026
- Known_Cve | Oct 17, 2026 | Part 2/416 Oct 2026
- 3 more on OTX