High severity7.5NVD Advisory· Published Apr 16, 2026· Updated May 22, 2026
CVE-2026-40170
CVE-2026-40170
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.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
42- osv-coords40 versionspkg:rpm/almalinux/ldb-toolspkg:rpm/almalinux/libldbpkg:rpm/almalinux/libldb-develpkg:rpm/almalinux/libnetapipkg:rpm/almalinux/libnetapi-develpkg:rpm/almalinux/libsmbclientpkg:rpm/almalinux/libsmbclient-develpkg:rpm/almalinux/libwbclientpkg:rpm/almalinux/libwbclient-develpkg:rpm/almalinux/python3-ldbpkg:rpm/almalinux/python3-sambapkg:rpm/almalinux/python3-samba-dcpkg:rpm/almalinux/python3-samba-testpkg:rpm/almalinux/sambapkg:rpm/almalinux/samba-clientpkg:rpm/almalinux/samba-client-libspkg:rpm/almalinux/samba-commonpkg:rpm/almalinux/samba-common-libspkg:rpm/almalinux/samba-common-toolspkg:rpm/almalinux/samba-dcerpcpkg:rpm/almalinux/samba-dc-libspkg:rpm/almalinux/samba-develpkg:rpm/almalinux/samba-gpupdatepkg:rpm/almalinux/samba-krb5-printingpkg:rpm/almalinux/samba-ldb-ldap-modulespkg:rpm/almalinux/samba-libspkg:rpm/almalinux/samba-pidlpkg:rpm/almalinux/samba-testpkg:rpm/almalinux/samba-test-libspkg:rpm/almalinux/samba-toolspkg:rpm/almalinux/samba-usersharespkg:rpm/almalinux/samba-vfs-iouringpkg:rpm/almalinux/samba-winbindpkg:rpm/almalinux/samba-winbind-clientspkg:rpm/almalinux/samba-winbind-krb5-locatorpkg:rpm/almalinux/samba-winbind-modulespkg:rpm/almalinux/samba-winexepkg:rpm/opensuse/ngtcp2&distro=openSUSE%20Tumbleweedpkg:rpm/opensuse/nodejs24&distro=openSUSE%20Tumbleweedpkg:rpm/opensuse/samba&distro=openSUSE%20Tumbleweed
< 4.23.5-109.el10_2+ 39 more
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- (no CPE)range: < 4.23.5-109.el10_2
- (no CPE)range: < 1.22.1-1.1
- (no CPE)range: < 24.17.0-1.1
- (no CPE)range: < 4.23.8+git.477.f78166bceed-1.1
Patches
Vulnerability mechanics
References
3- github.com/ngtcp2/ngtcp2/commit/708a7640c1f48fb8ffb540c4b8ea5b4c1dfb8ee5nvdPatch
- www.openwall.com/lists/oss-security/2026/04/17/12nvdExploitMailing ListMitigationPatchThird Party Advisory
- github.com/ngtcp2/ngtcp2/security/advisories/GHSA-f523-465f-8c8fnvdExploitMitigationPatchVendor Advisory
News mentions
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