CVE-2026-32179
Published:April 18, 2026
Updated:April 18, 2026
Summary Improper input validation in Microsoft QUIC allows an unauthorized attacker to elevate privileges over a network. Details Improper Input Validation Integer Underflow (Wrap or Wraparound) when decoding ACK frame. Patches - Fix underflow in ACK frame parsing - 1e6e999b Impact An attacker who successfully exploited this vulnerability could gain elevated privileges. MSRC CVE Info https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-32179
Affected Packages
https://github.com/microsoft/msquic.git (GITHUB):
Affected version(s) >=v0.9-draft-23 <v2.4.18Fix Suggestion:
Update to version v2.4.18https://github.com/microsoft/msquic.git (GITHUB):
Affected version(s) >=v2.5.0 <v2.5.7Fix Suggestion:
Update to version v2.5.7microsoft.native.quic.msquic.schannel (NUGET):
Affected version(s) >=1.8.0 <2.4.18Fix Suggestion:
Update to version 2.4.18microsoft.native.quic.msquic.openssl (NUGET):
Affected version(s) >=2.5.0-ci.532574 <2.5.7Fix Suggestion:
Update to version 2.5.7microsoft.native.quic.msquic.schannel (NUGET):
Affected version(s) >=2.5.0-ci.532574 <2.5.7Fix Suggestion:
Update to version 2.5.7microsoft.native.quic.msquic.openssl (NUGET):
Affected version(s) >=1.8.0 <2.4.18Fix Suggestion:
Update to version 2.4.18Related Resources (3)
Do you need more information?
Contact UsCVSS v4
Base Score:
9.3
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
HIGH
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
9.8
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Weakness Type (CWE)
Integer Underflow (Wrap or Wraparound)
