CVE-2026-9267 Eclipse Foundation CVE debrief

Who should care

Security teams and administrators responsible for managing and maintaining Eclipse tinydtls installations should be aware of this vulnerability. This vulnerability can be exploited by unauthenticated attackers, which makes it a significant concern for organizations that use Eclipse tinydtls in their products or services. Memory-constrained devices are particularly vulnerable to denial-of-service attacks.

Technical summary

The check_server_certificate() function in Eclipse tinydtls before commit b3efd41ad111a4920f599f51ffa4f5e9f1e72221 contains an out-of-bounds read vulnerability. This vulnerability occurs due to the lack of buffer length validation before performing uint24 reads, memcmp, and memcpy operations during DTLS epoch 0. An attacker can exploit this vulnerability by crafting a Certificate handshake message with a specific fragment_length value, allowing them to trigger reads beyond valid buffer boundaries. This can lead to denial-of-service attacks, particularly on memory-constrained devices.

Defensive priority

This vulnerability has a MEDIUM severity with a CVSS score of 6.9. It is essential to prioritize patching or mitigating this vulnerability, especially for memory-constrained devices.

Recommended defensive actions

• Apply the patch from commit b3efd41ad111a4920f599f51ffa4f5e9f1e72221 or later.
• Implement additional buffer length validation for uint24 reads, memcmp, and memcpy operations during DTLS epoch 0.
• Monitor and restrict incoming Certificate handshake messages with crafted fragment_length values.
• Perform regular security audits and vulnerability assessments to identify potential weaknesses.
• Consider implementing compensating controls, such as rate limiting or traffic filtering, to mitigate potential attacks.

Evidence notes

The CVE-2026-9267 vulnerability was identified in Eclipse tinydtls before commit b3efd41ad111a4920f599f51ffa4f5e9f1e72221. The vulnerability allows unauthenticated attackers to trigger out-of-bounds reads by crafting Certificate handshake messages. The CVSS score and severity are based on the official CVE record and NVD details. The source item URL provides additional information about the vulnerability.

Official resources