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Description

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.

PUBLISHED Reserved 2026-04-23 | Published 2026-05-18 | Updated 2026-05-18 | Assigner redhat




HIGH: 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Problem types

Undefined Behavior for Input to API

Product status

Default status
affected

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affected

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affected

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affected

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affected

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affected

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affected

Timeline

2026-05-06:Reported to Red Hat.
2026-04-29:Made public.

Credits

Red Hat would like to thank Joshua Rogers (AISLE Research Team) for reporting this issue.

References

access.redhat.com/security/cve/CVE-2026-42009 vdb-entry

bugzilla.redhat.com/show_bug.cgi?id=2467279 (RHBZ#2467279) issue-tracking

cve.org (CVE-2026-42009)

nvd.nist.gov (CVE-2026-42009)

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