Critical Security Flaw in compat-openssl10: DTLS Retransmits Handshake Messages from Stale Buffer Offset
Summary
RLSA-2026:80510: Important: compat-openssl10 security update. Affects compat-openssl10 versions < 1:1.0.2o-4.el8_10.4. Fixed in 1:1.0.2o-4.el8_10.4. How to fix ↓
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Background
The compat-openssl10 package provides essential libraries for secure communications, ensuring compatibility with software that relies on older versions of OpenSSL. This package is crucial for applications that have not yet transitioned to OpenSSL-1.1, allowing them to maintain secure connections. However, it is vulnerable to a significant security issue that could compromise data integrity and confidentiality.
Vulnerability Detail
The vulnerability identified as CVE-2026-84782 affects the compat-openssl10 package, where the DTLS (Datagram Transport Layer Security) protocol may retransmit handshake messages from a stale buffer offset. This flaw can lead to potential data exposure and unauthorized access, as attackers could exploit this weakness to intercept or manipulate secure communications. The vulnerability has a CVSS score of 7.4, indicating a high severity level that necessitates immediate attention.
How To Fix
Minimum fixed version
1:1.0.2o-4.el8_10.4
This is the first release that contains the fix.
sudo dnf update compat-openssl10Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, consider disabling DTLS if it is not critical for your application. However, this is not a long-term solution and updating the package is strongly advised.
Conclusion
The compat-openssl10 package is critical for maintaining secure communications in applications relying on older OpenSSL versions. The identified vulnerability, CVE-2026-84782, poses a significant risk, and it is essential to update to the patched version to mitigate potential security threats. Users are encouraged to utilize tools like Vulert to monitor for vulnerabilities in their software.
See every vulnerability recorded for compat-openssl10 →
FAQ
compat-openssl10 is a compatibility package that provides libraries for secure communications, specifically for applications that require older versions of OpenSSL.
CVE-2026-84782 describes a vulnerability in the DTLS protocol where handshake messages may be retransmitted from a stale buffer, potentially allowing attackers to exploit secure communications.
The vulnerability has a CVSS score of 7.4, indicating a high severity level that could lead to significant security risks if not addressed promptly.
You can use the Vulert playground at Vulert Scanner to check if your application is affected by this vulnerability without requiring any signup.
If an immediate update is not possible, consider disabling DTLS as a temporary workaround, but plan to update the package as soon as feasible.
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