CVE-2026-40170

HIGH

7.5

Description

ngtcp2 is a C implementation of the IETF QUIC protocol. In versions prior to 1.22.1, ngtcp2_qlog_parameters_set_transport_params() serializes peer transport parameters into a fixed 1024-byte stack buffer without bounds checking. When qlog is enabled, a remote peer can send sufficiently large transport parameters during the QUIC handshake to cause writes beyond the buffer boundary, resulting in a stack buffer overflow. This affects deployments that enable the qlog callback and process untrusted peer transport parameters. This issue has been fixed in version 1.22.1. If developers are unable to immediately upgrade, they can disable the qlog on client.

CVE Details

CVSS v3.1 Score7.5

SeverityHIGH

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredNONE

User InteractionNONE

Published4/16/2026

Last Modified4/17/2026

Sourcenvd

Honeypot Sightings0

Weaknesses (CWE)

CWE-121

References

https://github.com/ngtcp2/ngtcp2/commit/708a7640c1f48fb8ffb540c4b8ea5b4c1dfb8ee5(security-advisories@github.com)

https://github.com/ngtcp2/ngtcp2/security/advisories/GHSA-f523-465f-8c8f(security-advisories@github.com)

http://www.openwall.com/lists/oss-security/2026/04/17/12(af854a3a-2127-422b-91ae-364da2661108)

IOC Correlations

No correlations recorded

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