CVE-2026-40170 (GCVE-0-2026-40170)

Vulnerability from cvelistv5 – Published: 2026-04-16 21:34 – Updated: 2026-07-15 01:01
VLAI
Title
ngtcp2 has a qlog transport parameter serialization stack buffer overflow
Summary
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.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: poc Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-04-17 14:52 UTC
CWE
  • CWE-121 - Stack-based Buffer Overflow
  • CWE-120 - Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 7820 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
ngtcp2 ngtcp2 Affected: < 1.22.1
guessed Create a notification for this product.
Red Hat Red Hat Enterprise Linux 10 Unaffected: 0:4.23.5-109.el10_2 , < * (rpm)
    cpe:/o:redhat:enterprise_linux:10.2
Create a notification for this product.
Red Hat Red Hat Enterprise Linux 9 Unaffected: 0:4.23.5-10.el9_8 , < * (rpm)
    cpe:/a:redhat:enterprise_linux:9
    cpe:/o:redhat:enterprise_linux:9
Create a notification for this product.
Red Hat Red Hat Hardened Images Unaffected: 1.22.1-1.hum1 , < * (rpm)
    cpe:/a:redhat:hummingbird:1
Create a notification for this product.
Red Hat Red Hat Enterprise Linux 10     cpe:/o:redhat:enterprise_linux:10
Create a notification for this product.
Red Hat Red Hat Enterprise Linux 8     cpe:/o:redhat:enterprise_linux:8
Create a notification for this product.
Red Hat Red Hat Enterprise Linux 9     cpe:/o:redhat:enterprise_linux:9
Create a notification for this product.
Show details on NVD website
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}



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