Bug 2459061 (CVE-2026-40170) - CVE-2026-40170 ngtcp2: ngtcp2: Denial of service via stack buffer overflow during QUIC handshake
Summary: CVE-2026-40170 ngtcp2: ngtcp2: Denial of service via stack buffer overflow du...
Keywords:
Status: NEW
Alias: CVE-2026-40170
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
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Depends On: 2459282 2459283
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-04-16 22:01 UTC by OSIDB Bzimport
Modified: 2026-04-23 04:17 UTC (History)
0 users

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Description OSIDB Bzimport 2026-04-16 22:01:19 UTC 
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.
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