CVE-2026-49803
HIGH 7Concurrent execution using shared resource with improper synchronization ('race condition') in Windows AppX Deployment Service 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
0.2%chance of exploitation in 30 days · 5th 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 & exploit code
- github-search Search GitHub for public PoC repos
Test against your own equipment
curl -s https://vulnpedia.com/cve/CVE-2026-49803/poc.jsonMachine-readable PoC index for this CVE (for automation).Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-49803/poc.json
Affected
Vendors Microsoft
Products Windows 10 Version 1607 Windows 10 Version 1809 Windows 10 Version 21h2 Windows 10 Version 22h2 Windows 11 Version 24h2 Windows 11 Version 25h2 Windows 11 Version 26h1 Windows Server 2012 Windows Server 2012 (Server Core Installation) Windows Server 2012 R2 Windows Server 2012 R2 (Server Core Installation) Windows Server 2016
Weakness (CWE)
- CWE-362: : Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
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
Known Affected Software Configurations
| Vendor | Product | Version range |
|---|---|---|
| Microsoft | Windows 10 1607 | < 10.0.14393.9339 |
| Microsoft | Windows 10 1607 | < 10.0.14393.9339 |
| Microsoft | Windows 10 1809 | < 10.0.17763.9020 |
| Microsoft | Windows 10 1809 | < 10.0.17763.9020 |
| Microsoft | Windows 10 21h2 | < 10.0.19044.7548 |
| Microsoft | Windows 10 21h2 | < 10.0.19044.7548 |
| Microsoft | Windows 10 21h2 | < 10.0.19044.7548 |
| Microsoft | Windows 10 22h2 | < 10.0.19045.7548 |
| Microsoft | Windows 10 22h2 | < 10.0.19045.7548 |
| Microsoft | Windows 10 22h2 | < 10.0.19045.7548 |
| Microsoft | Windows 11 24h2 | < 10.0.26100.8875 |
| Microsoft | Windows 11 24h2 | < 10.0.26100.8875 |
| Microsoft | Windows 11 25h2 | < 10.0.26200.8875 |
| Microsoft | Windows 11 25h2 | < 10.0.26200.8875 |
| Microsoft | Windows 11 26h1 | < 10.0.28000.2269 |
| Microsoft | Windows 11 26h1 | < 10.0.28000.2525 |
| Microsoft | Windows Server 2012 | * |
| Microsoft | Windows Server 2012 | r2 |
| Microsoft | Windows Server 2016 | < 10.0.14393.9339 |
| Microsoft | Windows Server 2019 | < 10.0.17763.9020 |
| Microsoft | Windows Server 2022 | < 10.0.20348.5386 |
| Microsoft | Windows Server 2025 | < 10.0.26100.33158 |
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