Critical OpenSSL Vulnerability: DTLS Retransmits Handshake Messages from Stale Buffer Offset

openssl Updated 10 Oct 2026

Summary

06/10/2026

Disclosed on

N/A

Severity

Yes i

Fix available

Unrated

Severity

Not published

CVSS Score

ALSA-2026:76918: Important: openssl security update. Affects openssl versions < 1:3.5.8-2.el10_2.alma.1. Fixed in 1:3.5.8-2.el10_2.alma.1. How to fix ↓

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Background

OpenSSL is a widely-used toolkit that implements the Secure Sockets Layer (SSL) and Transport Layer Security (TLS) protocols, providing essential cryptographic functions for secure communications over networks. It is integral to many applications and services, ensuring data integrity and confidentiality. However, vulnerabilities in OpenSSL can lead to severe security risks, including unauthorized access and data breaches.

Vulnerability Detail

The vulnerability identified as CVE-2026-84782 allows DTLS (Datagram Transport Layer Security) to retransmit handshake messages from a stale buffer offset. This can potentially lead to exposure of sensitive information or unauthorized access to secure communications. The issue arises from improper handling of buffer offsets during the handshake process, which can be exploited by attackers to manipulate the communication flow.

How To Fix

Minimum fixed version

1:3.5.8-2.el10_2.alma.1

This is the first release that contains the fix.

sudo dnf update openssl

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Workaround

As a temporary workaround, consider disabling DTLS support in applications that utilize OpenSSL until the update can be applied. This may reduce the risk of exploitation but could affect the functionality of applications relying on DTLS.

Conclusion

The OpenSSL vulnerability CVE-2026-84782 poses significant risks to secure communications by allowing DTLS to retransmit handshake messages from a stale buffer. It is crucial to update to the patched version to safeguard against potential exploits. Utilizing tools like Vulert can help monitor and manage vulnerabilities effectively.

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