Security Digest · Vulnerability record
CVE-2026-32179: MsQuic has a Remote Elevation of Privilege Vulnerability
MsQuic has a Remote Elevation of Privilege Vulnerability
CVSS 9.8 Critical
Should you act?
Critical and remotely reachable
No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- No confirmed exploitation. It is not in CISA’s KEV catalog. That can change quickly after a public write-up; re-check if you are affected.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes
Microsoft.Native.Quic.MsQuic.OpenSSL(NuGet) >= 2.5.0-ci.532574, < 2.5.7, fixed in 2.5.7;Microsoft.Native.Quic.MsQuic.Schannel(NuGet) >= 2.5.0-ci.532574, < 2.5.7, fixed in 2.5.7;Microsoft.Native.Quic.MsQuic.Schannel(NuGet) < 2.4.18, fixed in 2.4.18;Microsoft.Native.Quic.MsQuic.OpenSSL(NuGet) < 2.4.18, fixed in 2.4.18. Check your lockfile, including transitive dependencies.
What it is
From the GitHub advisory
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.
Weakness type: CWE-191.
Product: Microsoft.Native.Quic.MsQuic.OpenSSL (NuGet) · Published: 2026-04-16
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| NuGet | Microsoft.Native.Quic.MsQuic.OpenSSL | >= 2.5.0-ci.532574, < 2.5.7 | 2.5.7 |
| NuGet | Microsoft.Native.Quic.MsQuic.Schannel | >= 2.5.0-ci.532574, < 2.5.7 | 2.5.7 |
| NuGet | Microsoft.Native.Quic.MsQuic.Schannel | < 2.4.18 | 2.4.18 |
| NuGet | Microsoft.Native.Quic.MsQuic.OpenSSL | < 2.4.18 | 2.4.18 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: none
- Scope: unchanged
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
Timeline
- — GitHub-reviewed advisory GHSA-gvvw-8j96-8g5r published (critical)
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-gvvw-8j96-8g5r github.com
- CVE.org record CVE-2026-32179 cve.org
- NVD entry CVE-2026-32179 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com
- github.com github.com