CVE-2026-59134
HIGH 7.5 ALL-YEARSHeap-based buffer overflow in Remote Desktop Client allows an unauthorized attacker to execute code over a network.
Severe if exploited (CVSS 7.5), but no confirmed exploitation. Patch on a normal cadence.
Exploitation likelihood
0.7%chance of exploitation in 30 days · 52nd percentile
Impact if exploited
7.5CVSS 3.1 · HIGH · CNA
- ConfidentialityHigh
- IntegrityHigh
- AvailabilityHigh
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ✓Privileges: No account or privileges required
- ⚠User interaction: A user must take an action (click / open a file)
- ⚠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.
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Tracked sources are checked weekly for the full archive, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.
Affected
Vendors Microsoft
Products Windows 10 Version 1607 Windows 10 Version 1809 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 Server 2012 Windows Server 2012 (Server Core Installation) Windows Server 2012 R2 Windows Server 2012 R2 (Server Core Installation) Windows Server 2016 Windows Server 2016 (Server Core Installation) Windows Server 2019 Windows Server 2019 (Server Core Installation) Windows Server 2022 Windows Server 2025 Windows Server 2025 (Server Core Installation) Windows 10 1607 Windows 10 1809 Windows 10 21h2 Windows 10 22h2 Windows 11 23h2 Windows 11 24h2 Windows 11 25h2 Windows 11 26h1
Weakness (CWE)
- CWE-122: : Heap-based Buffer Overflow
- CWE-20: : Improper Input Validation
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
References and research data (JSON)
Known Affected Software Configurations
| Vendor | Product | Version range |
|---|---|---|
| Microsoft | Windows 10 1607 | < 10.0.14393.9418 |
| Microsoft | Windows 10 1607 | < 10.0.14393.9418 |
| Microsoft | Windows 10 1809 | < 10.0.17763.9115 |
| Microsoft | Windows 10 1809 | < 10.0.17763.9115 |
| Microsoft | Windows 10 21h2 | < 10.0.19044.7663 |
| Microsoft | Windows 10 21h2 | < 10.0.19044.7663 |
| Microsoft | Windows 10 21h2 | < 10.0.19044.7663 |
| Microsoft | Windows 10 22h2 | < 10.0.19045.7663 |
| Microsoft | Windows 10 22h2 | < 10.0.19045.7663 |
| Microsoft | Windows 10 22h2 | < 10.0.19045.7663 |
| Microsoft | Windows 11 23h2 | < 10.0.22631.7517 |
| Microsoft | Windows 11 23h2 | < 10.0.22631.7517 |
| Microsoft | Windows 11 24h2 | < 10.0.26100.9106 |
| Microsoft | Windows 11 24h2 | < 10.0.26100.9106 |
| Microsoft | Windows 11 25h2 | < 10.0.26200.9106 |
| Microsoft | Windows 11 25h2 | < 10.0.26200.9106 |
| Microsoft | Windows 11 26h1 | < 10.0.28000.2704 |
| Microsoft | Windows 11 26h1 | < 10.0.28000.2704 |
| Microsoft | Windows Server 2012 | * |
| Microsoft | Windows Server 2012 | r2 |
| Microsoft | Windows Server 2016 | < 10.0.14393.9418 |
| Microsoft | Windows Server 2019 | < 10.0.17763.9115 |
| Microsoft | Windows Server 2022 | < 10.0.20348.5440 |
| Microsoft | Windows Server 2025 | < 10.0.26100.33222 |
All CVSS metrics
- HIGH 7.5 v3.1 · CNA Primary
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C - HIGH 7.5 v3.1 · NVD Secondary
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H - HIGH 8.1 v3.1 · NVD Primary
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
References
Patches & mitigations
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-59134 CVE record · microsoft · Updated 2026-10-21T20:51:26.680Z
NVD · CVE-2026-59134 · Updated 2026-08-16T19:16:45.760
Advisories
- https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-56314 EUVD · EUVD-2026-56314
Sources: NVD · CVE.org · All sources and attribution · EPSS