Affects Microsoft Windows SMB service, a widely deployed core service; authenticated RCE in SMB can enable broad disruption and widespread compromise.
CVE-2026-62800
SMB server heap overflow allows authenticated remote code execution.
Is CVE-2026-62800 being exploited?
Not confirmed. CVE-2026-62800 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 0.93% probability of exploitation in the next 30 days.
How severe is CVE-2026-62800?
CVE-2026-62800 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-2026-62800?
Yes. A fix has been recorded for CVE-2026-62800. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-62800 affect?
CVE-2026-62800 affects Microsoft Windows SMB Server, Windows Server (supported releases), Windows Desktop (supported releases). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-62800?
Restrict/block SMB (TCP 445), apply vendor patch when released, and monitor SMB logs
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Authenticated attacker can trigger SMB heap overflow to execute arbitrary code remotely as SYSTEM, enabling full system compromise and lateral movement.
Immediate action required
- affected>= 10.0.14393.0 and < 10.0.14393.9418
- affected>= 10.0.17763.0 and < 10.0.17763.9121
- affected>= 10.0.19044.0 and < 10.0.19044.7663
- affected>= 10.0.19045.0 and < 10.0.19045.7663
- affected>= 10.0.22631.0 and < 10.0.22631.7517
- affected>= 10.0.22631.0 and < 10.0.22631.7517
- affected>= 10.0.26100.0 and < 10.0.26100.9168
- affected>= 10.0.26200.0 and < 10.0.26200.9168
- affected>= 10.0.28000.0 and < 10.0.28000.2704
- affected>= 6.2.9200.0 and < 6.2.9200.26280
- affected>= 6.3.9600.0 and < 6.3.9600.23338
- affected>= 6.3.9600.0 and < 6.3.9600.23338
- affected>= 6.2.9200.0 and < 6.2.9200.26280
- affected>= 10.0.14393.0 and < 10.0.14393.9418
- affected>= 10.0.14393.0 and < 10.0.14393.9418
- affected>= 10.0.17763.0 and < 10.0.17763.9121
- affected>= 10.0.17763.0 and < 10.0.17763.9121
- affected>= 10.0.20348.0 and < 10.0.20348.5499
- affected>= 10.0.26100.0 and < 10.0.26100.33296
- affected>= 10.0.26100.0 and < 10.0.26100.33296
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.