CVE-2026-40170
highngtcp2 is a C implementation of the IETF QUIC protocol.
Vendor / product: Tatsuhiro-t — ngtcp2
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Affected products
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
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
- https://access.redhat.com/errata/RHSA-2026:22963 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- https://access.redhat.com/errata/RHSA-2026:25049 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- https://access.redhat.com/errata/RHSA-2026:9113 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- https://access.redhat.com/security/cve/CVE-2026-40170 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- https://bugzilla.redhat.com/show_bug.cgi?id=2459061 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- https://github.com/ngtcp2/ngtcp2/security/advisories/GHSA-f523-465f-8c8f 134c704f-9b21-4f2e-91b3-4a467353bcc0
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40170.json 0b0ca135-0b70-47e7-9f44-1890c2a1c46c