# CVE-2026-105512: Microsoft QUIC integer underflow denial of service

Source: https://junglewise.ai/threats/cve-2026-105512-integer-underflow-wrap-or-wraparound-in-microsoft-quic-allows-an  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-10. Updated: 2026-11-10  
License: CC BY 4.0 with a link back

CVE-2026-105512 · Severity: high · CVSS 7.5 · Published 2026-11-10

Microsoft QUIC is a network protocol implementation used in Windows and other products to enable fast, secure communications. An integer underflow vulnerability in QUIC allows an attacker to crash or disable systems using the protocol by sending specially crafted network packets, causing a denial of service.

Technologies: [Microsoft QUIC](https://junglewise.ai/threats/technologies/microsoft-quic). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2026-105512 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-105512 being exploited in the wild.

**How severe is CVE-2026-105512?** High severity, with a CVSS score of 7.5, published 10 November 2026.

**Which products and versions are affected?** Microsoft QUIC.

**Is there a fix for CVE-2026-105512?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-105512 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-105512?** Check whether you run Microsoft QUIC. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

An integer underflow (wraparound) vulnerability in Microsoft QUIC allows an attacker to trigger a denial of service condition by sending malformed QUIC protocol packets over a network. The vulnerability requires no authentication or user interaction; the attack vector is network-based. A successful exploit crashes the QUIC implementation or causes the affected system to become unresponsive.

## Affected products

- Microsoft QUIC

## Timeline

- 2026-11-10: disclosed

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-105512](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-105512)

## Related threats

- [Microsoft QUIC null pointer dereference DoS](https://junglewise.ai/threats/cve-2026-88236-null-pointer-dereference-in-microsoft-quic-allows-an-unauthorized)
- [Microsoft QUIC insecure default variable initialization](https://junglewise.ai/threats/cve-2026-103577-insecure-default-variable-initialization-in-microsoft-quic)
- [Microsoft QUIC use-after-free remote code execution](https://junglewise.ai/threats/cve-2026-100219-use-after-free-in-microsoft-quic-allows-an-unauthorized-attacker)