CVE-2026-33846

Published May 4, 2026

Last updated 3 days ago

CVSS high 7.5
Tls

Overview

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.
Source
secalert@redhat.com
NVD status
Awaiting Analysis

Risk scores

CVSS 3.1

Type
Secondary
Base score
7.5
Impact score
3.6
Exploitability score
3.9
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Severity
HIGH

Weaknesses

secalert@redhat.com
CWE-130
0b0ca135-0b70-47e7-9f44-1890c2a1c46c
CWE-130

Social media

Hype score
Not currently trending

  1. 🚨 HIGH: CVE-2026-33846 - GnuTLS DTLS heap buffer overflow (CVSS 7.5). Remotely exploitable without auth. Affects DTLS handshake fragment reassembly. Patch immediately. #CVE #Vulnerability #PatchNow #ThreatIntel https://t.co/YgpzyQyB3V

    @DFIR_Lab

    24 May 2026

    47 Impressions

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Related CVEs

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References

Sources include official advisories and independent security research.