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CVE-2026-42009

high

A flaw was found in gnutls.

Vendor / product: Gnu — gnutls

A flaw was found in gnutls. A remote attacker could exploit an issue in the Datagram Transport Layer Security (DTLS) packet reordering logic. The comparator function, responsible for ordering DTLS packets by sequence numbers, did not correctly handle packets with duplicate sequence numbers. This could lead to unstable packet ordering or undefined behavior, resulting in a denial of service.

CVSS
7.5
7.5 (CVSS v3.1)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Severity source: NVD CVSS v3.1 (secalert@redhat.com)
Timeline (UTC)
Published: 2026-05-18 13:16
Modified: 2026-10-30 17:17
NVD status: Modified
Last synced 20 hours ago
Verified against the source API 2026-10-30 17:47 UTC
Exploitation
Not listed in CISA KEV (as of last catalog sync)
Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).

Affected products

gnu / gnutls all versions
redhat / hardened_images all versions
redhat / openshift_container_platform 4.0
redhat / enterprise_linux 6.0, 7.0, 8.0, 9.0, 9.8, 10.0
redhat / enterprise_linux_for_els 8.10, 9.8, 10.2
redhat / enterprise_linux_for_ibm_z_systems 8.0_s390x, 9.0_s390x, 10.2
redhat / enterprise_linux_for_ibm_z_systems_els 8.10, 9.8, 10.2
redhat / enterprise_linux_for_power_little_endian 8.0_ppc64le, 9.0_ppc64le, 10.0, 10.2
redhat / enterprise_linux_for_power_little_endian_els 8.10, 9.8, 10.2
redhat / enterprise_linux_for_eus 9.8, 10.2
redhat / enterprise_linux_for_ibm_z_systems_eus 9.8, 10.2
redhat / enterprise_linux_for_power_little_endian_eus 9.8, 10.2
redhat / enterprise_linux_for_update_services_for_sap_solutions 9.8
redhat / enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions 9.8

Weakness classification (CWE)

CWE-475

Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.

Mitigation & advisories

No vendor advisory or patch reference tagged by NVD. Check the references below.

References

Data sources

NVD CVE API 2.0 — fetched 2026-10-30 17:47 UTC · record ↗

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