A heap buffer overflow vulnerability exists in the DTLS handshake fragment reassembly logic of GnuTLS. The issue arises in merge_handshake_packet() where incoming handshake fragments are matched and merged based solely on handshake type, without validating that the message_length field remains consistent across all fragments of the same logical message. An attacker can exploit this by sending crafted DTLS fragments with conflicting message_length values, causing the implementation to allocate a buffer based on a smaller initial fragment and subsequently write beyond its bounds using larger, inconsistent fragments. Because the merge operation does not enforce proper bounds checking against the allocated buffer size, this results in an out-of-bounds write on the heap. The vulnerability is remotely exploitable without authentication via the DTLS handshake path and can lead to application crashes or potential memory corruption.

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Advisories
Source ID Title
Debian DLA Debian DLA DLA-4595-1 gnutls28 security update
Debian DSA Debian DSA DSA-6281-1 gnutls28 security update
Ubuntu USN Ubuntu USN USN-8284-1 GnuTLS vulnerabilities
Fixes

Solution

No solution given by the vendor.


Workaround

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

History

Mon, 04 May 2026 20:15:00 +0000

Type Values Removed Values Added
First Time appeared Gnu
Gnu gnutls
Redhat hardened Images
Redhat openshift Container Platform
Vendors & Products Gnu
Gnu gnutls
Redhat hardened Images
Redhat openshift Container Platform

Mon, 04 May 2026 13:30:00 +0000

Type Values Removed Values Added
References

Mon, 04 May 2026 13:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Mon, 04 May 2026 12:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Important


Mon, 04 May 2026 09:30:00 +0000

Type Values Removed Values Added
Description A heap buffer overflow vulnerability exists in the DTLS handshake fragment reassembly logic of GnuTLS. The issue arises in merge_handshake_packet() where incoming handshake fragments are matched and merged based solely on handshake type, without validating that the message_length field remains consistent across all fragments of the same logical message. An attacker can exploit this by sending crafted DTLS fragments with conflicting message_length values, causing the implementation to allocate a buffer based on a smaller initial fragment and subsequently write beyond its bounds using larger, inconsistent fragments. Because the merge operation does not enforce proper bounds checking against the allocated buffer size, this results in an out-of-bounds write on the heap. The vulnerability is remotely exploitable without authentication via the DTLS handshake path and can lead to application crashes or potential memory corruption.
Title Gnutls: gnutls: denial of service via heap buffer overflow in dtls handshake fragment reassembly
First Time appeared Redhat
Redhat enterprise Linux
Redhat hummingbird
Redhat openshift
Weaknesses CWE-130
CPEs cpe:/a:redhat:hummingbird:1
cpe:/a:redhat:openshift:4
cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:6
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
Redhat hummingbird
Redhat openshift
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-05-14T05:26:14.067Z

Reserved: 2026-03-24T05:31:54.914Z

Link: CVE-2026-33846

cve-icon Vulnrichment

Updated: 2026-05-04T12:46:48.609Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-05-04T10:15:59.690

Modified: 2026-05-04T15:22:52.850

Link: CVE-2026-33846

cve-icon Redhat

Severity : Important

Publid Date: 2026-05-04T08:53:59Z

Links: CVE-2026-33846 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-05-04T19:44:12Z

Weaknesses