Type Vulnerability
Heap-based buffer overflow in Xbox allows an unauthorised attacker to execute code over a network.
Microsoft · Code execution
Microsoft Xbox Remote Code Execution Vulnerability
CVE-2026-66801
What this means
This is rated critical severity (9.8 out of 10). There is no confirmed exploitation of it yet. Ask IT whether the affected products are in your estate.
Full vendor description
Heap-based buffer overflow in Xbox allows an unauthorized attacker to execute code over a network.
Scoring and exploitation
9.8/ 10
CVSS 3.1 base scoreCritical
Exploitable over the network without any account, and no one has to click or open anything. High impact on confidentiality, integrity and availability.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploitability
Longer bar: easier to attack
Attack vectorNetworkAV:N
Attack complexityLowAC:L
Privileges requiredNonePR:N
User interactionNoneUI:N
ScopeUnchangedS:U
Impact
Longer bar: more harm
ConfidentialityHighC:H
IntegrityHighI:H
AvailabilityHighA:H
- Not reported
- Exploited in the wild
- Not confirmed in the
- Not reported
Weaknesses
CWE-122
References
1 link from the CVE record, grouped by site.
msrc.microsoft.com1 link