CVE-2026-2798
DOM use-after-free in Firefox/Thunderbird before 148.
Is CVE-2026-2798 being exploited?
Not confirmed. CVE-2026-2798 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.25% probability of exploitation in the next 30 days.
How severe is CVE-2026-2798?
CVE-2026-2798 is rated High with a CVSS score of 8.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-2798?
Yes. A fix has been recorded for CVE-2026-2798. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-2798 affect?
CVE-2026-2798 affects Mozilla Firefox < 148, Mozilla Thunderbird < 148. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-2798?
Update to Firefox/Thunderbird 148+
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote code execution via crafted DOM content in Firefox/Thunderbird <148.
Patch when possible