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Not yet scoredPublished Oct 13, 2026
CVE-2026-109759Site isolation issue in the Networking component
Updated under an hour ago ()
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It affects Mozilla Firefox and 1 other product. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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Site isolation issue in the Networking component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
- CVSS
- Not yet scored
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- mozilla
- NVD analysis
- Deferred
- Record last updated
- Oct 13, 2026
- First seen by InfoSec Signals
- Oct 13, 2026
Affected products
Mozilla Firefox mozilla:firefox (from the name) | 153.5 builds before 153.* not affected; from 158 not affected | CNA record |
Mozilla Thunderbird mozilla:thunderbird (from the name) | 153.5 builds before 153.* not affected; from 158 not affected | CNA record |
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2070252
- https://www.mozilla.org/security/advisories/mfsa2026-106/
- https://www.mozilla.org/security/advisories/mfsa2026-108/
- https://www.mozilla.org/security/advisories/mfsa2026-109/
- https://www.mozilla.org/security/advisories/mfsa2026-110/
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.