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

CWE-120

https://access.redhat.com/errata/RHSA-2026:22963

https://access.redhat.com/errata/RHSA-2026:25049

https://access.redhat.com/errata/RHSA-2026:9113

https://access.redhat.com/security/cve/CVE-2026-40170

https://bugzilla.redhat.com/show_bug.cgi?id=2459061

https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40170.json

[{"vendor":"Red Hat","product":"Red Hat Enterprise Linux AppStream (v. 10)","defaultStatus":"affected","cpes":["cpe:/o:redhat:enterprise_linux:10.2"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux AppStream (v. 9)","defaultStatus":"affected","cpes":["cpe:/a:redhat:enterprise_linux:9::appstream"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux BaseOS (v. 10)","defaultStatus":"affected","cpes":["cpe:/o:redhat:enterprise_linux:10.2"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux BaseOS (v. 9)","defaultStatus":"affected","cpes":["cpe:/o:redhat:enterprise_linux:9::baseos"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)","defaultStatus":"affected","cpes":["cpe:/o:redhat:enterprise_linux:10.2"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)","defaultStatus":"affected","cpes":["cpe:/a:redhat:enterprise_linux:9::crb"]},{"vendor":"Red Hat","product":"Red Hat Hardened Images","defaultStatus":"affected","cpes":["cpe:/a:redhat:hummingbird:1"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux Resilient Storage (v. 9)","defaultStatus":"affected","cpes":["cpe:/a:redhat:enterprise_linux:9::resilientstorage"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 10","defaultStatus":"unaffected","cpes":["cpe:/o:redhat:enterprise_linux:10"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 8","defaultStatus":"unaffected","cpes":["cpe:/o:redhat:enterprise_linux:8"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","defaultStatus":"unaffected","cpes":["cpe:/o:redhat:enterprise_linux:9"]}]

{"timestamp":"2026-04-17T14:52:12.292330Z","id":"CVE-2026-40170","options":[{"exploitation":"poc"},{"automatable":"yes"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}

[{"vendor":"ngtcp2","product":"ngtcp2","versions":[{"version":"< 1.22.1","status":"affected"}]}]

OR
          *cpe:2.3:a:nghttp2:ngtcp2:*:*:*:*:*:*:*:* versions up to (excluding) 1.22.1

OR
          *cpe:2.3:a:tatsuhiro-t:ngtcp2:*:*:*:*:*:*:*:* versions up to (excluding) 1.22.1

OR
          *cpe:2.3:a:nghttp2:ngtcp2:*:*:*:*:*:*:*:* versions up to (excluding) 1.22.1

CISA-ADP: https://github.com/ngtcp2/ngtcp2/security/advisories/GHSA-f523-465f-8c8f Types: Exploit, Mitigation, Patch, Vendor Advisory

CVE: http://www.openwall.com/lists/oss-security/2026/04/17/12 Types: Exploit, Mailing List, Mitigation, Patch, Third Party Advisory

GitHub, Inc.: https://github.com/ngtcp2/ngtcp2/commit/708a7640c1f48fb8ffb540c4b8ea5b4c1dfb8ee5 Types: Patch

GitHub, Inc.: https://github.com/ngtcp2/ngtcp2/security/advisories/GHSA-f523-465f-8c8f Types: Exploit, Mitigation, Patch, Vendor Advisory

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

http://www.openwall.com/lists/oss-security/2026/04/17/12

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.

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

CWE-121

https://github.com/ngtcp2/ngtcp2/commit/708a7640c1f48fb8ffb540c4b8ea5b4c1dfb8ee5

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