CVE-2026-83676
HIGH 7Integer underflow (wrap or wraparound) in Windows Installer allows an authorized attacker to elevate privileges locally.
Severe if exploited (CVSS 7), but no known exploitation and low modeled probability. Patch on a normal cadence.
Exploitation likelihood
0.3%chance of exploitation in 30 days · 21st percentile
Impact if exploited
7CVSS 3.1 · HIGH
- ConfidentialityHigh
- IntegrityHigh
- AvailabilityHigh
What an attacker needs
- ⚠Access: Requires local access to the host
- ⚠Privileges: Requires a low-privilege account
- ✓User interaction: No user interaction needed
- ⚠Complexity: Needs a race window or specific setup
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept
No public PoC is currently catalogued.
Search for new PoCs
Search GitHub now — results may be empty or unverified.
Tracked sources are checked daily for recent CVEs, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.
Data snapshot:
Affected
Vendors Microsoft
Products Windows 10 Version 21h2 Windows 10 Version 22h2 Windows 11 Version 23h2 Windows 11 Version 24h2 Windows 11 Version 25h2 Windows 11 Version 26h1 Windows 11 Version 26h2 Windows Server 2022 Windows Server 2025 Windows Server 2025 (Server Core Installation)
Weakness (CWE)
- CWE-191: : Integer Underflow (Wrap or Wraparound)
- CWE-122: : Heap-based Buffer Overflow
CVSS vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
References and research data (JSON)
All CVSS metrics
- HIGH 7 v3.1 · CNA Primary
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C - HIGH 7 v3.1 · NVD Secondary
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
References
Patches & mitigations
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83676 CVE record · microsoft · Updated 2026-10-25T18:45:12.158Z
NVD · CVE-2026-83676 · Updated 2026-10-16T16:21:15.520
Advisories
- https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-99944 EUVD · EUVD-2026-99944