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CVE-2026-33846

HIGHCVSS 7.5/10EPSS 1.26%

Last modified

CVE-2026-33846 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 1.26% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
7.5/10

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

EPSS Probability
1.26%

66.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
Red HatRed Hat Enterprise Linux 10All versions
Red HatRed Hat Enterprise Linux 10.0 Extended Update SupportAll versions
Red HatRed Hat Enterprise Linux 7 Extended Lifecycle SupportAll versions
Red HatRed Hat Enterprise Linux 8All versions
Red HatRed Hat Enterprise Linux 8.4 Advanced Mission Critical Update SupportAll versions
Red HatRed Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-OnAll versions
Red HatRed Hat Enterprise Linux 8.6 Advanced Mission Critical Update SupportAll versions
Red HatRed Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-OnAll versions
Red HatRed Hat Enterprise Linux 8.8 Telecommunications Update ServiceAll versions
Red HatRed Hat Enterprise Linux 8.8 Update Services for SAP SolutionsAll versions
Red HatRed Hat Enterprise Linux 9All versions
Red HatRed Hat Enterprise Linux 9.2 Update Services for SAP SolutionsAll versions
Red HatRed Hat Enterprise Linux 9.4 Update Services for SAP SolutionsAll versions
Red HatRed Hat Enterprise Linux 9.6 Extended Update SupportAll versions
Red HatRed Hat AI Inference Server 3.2All versions
Red HatRed Hat Discovery 2All versions
Red HatRed Hat Hardened ImagesAll versions
Red HatRed Hat Update Infrastructure 5All versions
Red HatRed Hat OpenShift Container Platform 4All versions

References

Timeline

Published
Last Modified
Status
Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-33846?
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.
How severe is CVE-2026-33846?
CVE-2026-33846 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 1.26% probability of exploitation in the next 30 days.
How do I fix CVE-2026-33846?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST