CVE-2026-21637MediumMicrosoft CVSS 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C

Microsoft security update for CVE-2026-21637 — Microsoft Visual Studio

Published
June 2, 2026
Last Modified
—

🔗 CVE IDs covered (1)

CVE-2026-21637 →

📋 Microsoft's advisory

EchelonGraph does not copy Microsoft's advisory page: its FAQ and remediation text are not shown here. Read the advisory on https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21637. This page also shows what EchelonGraph holds for CVE-2026-21637, with the description from its CVE record, which the CVE Numbering Authority that assigned the CVE wrote: for a CVE Microsoft assigned, often in the words of Microsoft's own advisory.

🎯 Affected products3

  • Microsoft Visual Studio 2019 version 16.11 (includes 16.0 - 16.10)
  • Microsoft Visual Studio 2022 version 17.12
  • Microsoft Visual Studio 2022 version 17.14

✅ Updates Microsoft lists: 3 updates

3 rows: one per KB article or update, update type and fixed build. Their details are on Microsoft's advisory.

KB articleUpdateFixed build
—Security Update16.11.55
—Security Update17.12.19
—Security Update17.14.30

🧭 EchelonGraph on CVE-2026-21637

EchelonGraph score
7.5 HIGH
CISA KEV
Not listed
Fix status
A fix is available — apply it.

Description from the CVE record (CVE.org), as published by its numbering authority

A flaw in Node.js TLS error handling allows remote attackers to crash or exhaust resources of a TLS server when `pskCallback` or `ALPNCallback` are in use. Synchronous exceptions thrown during these callbacks bypass standard TLS error handling paths (tlsClientError and error), causing either immediate process termination or silent file descriptor leaks that eventually lead to denial of service. Because these callbacks process attacker-controlled input during the TLS handshake, a remote client can repeatedly trigger the issue. This vulnerability affects TLS servers using PSK or ALPN callbacks across Node.js versions where these callbacks throw without being safely wrapped.

Published by HackerOne, the CVE Numbering Authority that assigned CVE-2026-21637, in its CVE record at CVE.org; reused under the CVE Program's Terms of Use (its licence and MITRE's copyright notice are in our Terms of Service).

🔗 References (5)