CVE-2026-33846 | Gnutls: gnutls: denial of service via heap buffer overflow in dtls handshake fragment reassembly

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.

Published: 2026-05-04 Last update: 2026-06-02 Assigner: [email protected] Source: [email protected]
NVD Status：Awaiting Analysis，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-33846 is rated Low Risk (36.2/100): CVSS High severity, with low exploitation likelihood (EPSS 0.06%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-33846

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-02 0.02% 0.06% +0.03%
2 2026-05-22 0.06% 0.02% -0.04%
3 2026-05-04 — 0.06% —

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-33846

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2026-33846

GitHub Security Advisory for CVE-2026-33846

GHSA-qcj7-gqxf-2cqq · Severity: high — A heap buffer overflow vulnerability exists in the DTLS handshake fragment reassembly logic of...

OS Trackers for CVE-2026-33846

vendor priority summary link
debian not yet assigned CVE-2026-33846 not yet assigned priority: Debian including 1 source packages (gnutls28), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2026-33846
redhat high — https://access.redhat.com/security/cve/CVE-2026-33846
suse high CVE-2026-33846 severity important: SUSE including 10 source package names (gnutls-3.8.13-1.1, libgnutls-dane-devel-3.8.13-1.1, …), 10 product×package rows across 1 product lines (openSUSE Tumbleweed): Fixed 10. https://www.suse.com/security/cve/CVE-2026-33846/
ubuntu medium CVE-2026-33846 medium priority: Ubuntu including 1 source packages (gnutls28), 8 status rows across 8 suites (bionic, focal, jammy, noble, questing, resolute, upstream, xenial): released 5, needs-triage 3. https://ubuntu.com/security/CVE-2026-33846

Affected software / configurations for CVE-2026-33846

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-33846

cvelogic Threat Intelligence