Moderate Vulnerability in OpenSSL: Denial of Service Due to NULL Pointer Dereference
Summary
RLSA-2026:22312: Moderate: openssl security update. Affects openssl versions < 1:3.5.5-3.el9_8. Fixed in 1:3.5.5-3.el9_8. 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, along with a comprehensive general-purpose cryptography library. It is essential for securing communications over computer networks. The package is integral to many applications and services, providing encryption and secure data transmission. However, it is susceptible to vulnerabilities that can compromise its functionality and security.
Vulnerability Detail
The vulnerability identified as CVE-2026-28390 in OpenSSL is a Denial of Service (DoS) issue caused by a NULL pointer dereference during the processing of CMS EnvelopedData. This flaw can be exploited by an attacker to crash the application using OpenSSL, leading to service interruptions. The technical aspect of this vulnerability lies in the improper handling of certain inputs, which can trigger the NULL pointer dereference, resulting in application instability.
How To Fix
Minimum fixed version
1:3.5.5-3.el9_8
This is the first release that contains the fix.
sudo dnf update opensslTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, you can limit the exposure of your application by implementing stricter input validation and error handling to prevent the processing of malformed CMS EnvelopedData. However, this is not a substitute for applying the official patch.
Conclusion
The OpenSSL vulnerability CVE-2026-28390 poses a moderate risk due to its potential to cause Denial of Service through NULL pointer dereference. It is crucial to update to the patched version to safeguard your applications. Implementing workarounds can provide temporary relief, but they should not replace proper patch management.
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FAQ
CVE-2026-28390 is a vulnerability in OpenSSL that allows for a Denial of Service due to a NULL pointer dereference in CMS EnvelopedData processing.
Exploitation of this vulnerability can lead to application crashes, resulting in service downtime and potential data loss.
Yes, a patch is available in the form of OpenSSL version 1:3.5.5-3.el9_8, which addresses this vulnerability.
If immediate updating is not possible, consider implementing stricter input validation and error handling as a temporary workaround.
You can use Vulert, which monitors and alerts for open-source vulnerabilities in your software using just a manifest file like package-lock.json. You can check your application for this vulnerability using the Vulert playground without any signup.
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