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CVE-2026-40170

nvd nist
Published: Apr 16, 2026Modified: Jul 15, 2026

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7.5
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Exploitability: 3.9 / Impact: 3.6
Source: security-advisories@github.com (Secondary)

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.

Affected (1)

Products: Tatsuhiro T: Ngtcp2
Tatsuhiro T
1 product
Ngtcp2
Configuration A
1 vulnerable
Vulnerable SoftwareAffected Versions
Ngtcp2
Before 1.22.1

Related CWEs

CWE-120
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow.
CWE-121
Stack-based Buffer Overflow
A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).

References (10)

Source: security-advisories@github.com
Patch
Source: security-advisories@github.com
ExploitMitigationPatchVendor Advisory
Source: af854a3a-2127-422b-91ae-364da2661108
ExploitMailing ListMitigationPatchThird Party Advisory
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
ExploitMitigationPatchVendor Advisory
Source: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

Timeline

No history available yet.