CVE-2026-33846 Gnutls: gnutls: denial of service via heap buffer overflow in dtls handshake fragment reassembly
Remote attackers can cause denial of service or potential code execution via heap buffer overflow in GnuTLS DTLS handshake fragment reassembly.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-33846?
CVE-2026-33846 is a high-severity memory corruption vulnerability in Cert Manager support for Red Hat OpenShift release 1.17, published on 4 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-130
Which versions are affected by CVE-2026-33846?
How do I fix CVE-2026-33846?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-33846 being exploited?
There is no known exploitation of CVE-2026-33846 in the wild and no public exploit code.
Sources
Also known as ALPINE-CVE-2026-33846, AZL-86220, BELL-CVE-2026-33846, DEBIAN-CVE-2026-33846, ECHO-b6ab-fa46-b1fc, GHSA-qcj7-gqxf-2cqq and 4 more.