Moderate Vulnerability in compat-openssl11: Denial of Service Risk Due to NULL Pointer Dereference
Summary
ALSA-2026:22313: Moderate: compat-openssl11 security update. Affects compat-openssl11 versions < 1:1.1.1k-5.el9_8.3. Fixed in 1:1.1.1k-5.el9_8.3. How to fix ↓
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Background
The compat-openssl11 package is a compatibility layer for the OpenSSL toolkit, specifically designed for AlmaLinux 9. It provides essential libraries from the OpenSSL 1.1.1 version, enabling secure communications between machines. This package is crucial for applications that rely on OpenSSL for encryption and secure data transmission, making it a vital component in maintaining application security.
Vulnerability Detail
The vulnerability identified as CVE-2026-28390 involves a Denial of Service (DoS) risk stemming from a NULL pointer dereference during the processing of CMS EnvelopedData in OpenSSL. This flaw can be exploited by an attacker to crash the application or service utilizing the affected OpenSSL libraries, leading to potential downtime and service disruption. The vulnerability arises from improper handling of certain data structures within the OpenSSL library, which can be triggered under specific conditions.
How To Fix
Minimum fixed version
1:1.1.1k-5.el9_8.3
This is the first release that contains the fix.
sudo dnf update compat-openssl11Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, you may consider disabling any features or services that utilize the affected OpenSSL libraries until the package can be updated. However, this may not be feasible for all applications, and updating is the preferred solution.
Conclusion
The compat-openssl11 package has a moderate vulnerability that poses a Denial of Service risk due to a NULL pointer dereference. It is crucial to update to the patched version to mitigate this risk and ensure the security and stability of applications relying on OpenSSL.
See every vulnerability recorded for compat-openssl11 →
FAQ
CVE-2026-28390 is a vulnerability in the OpenSSL library that can lead to a Denial of Service due to a NULL pointer dereference in CMS EnvelopedData processing.
Exploitation of this vulnerability can cause your application to crash, leading to service interruptions and potential downtime.
Yes, a patched version of the compat-openssl11 package is available. Updating to version 1:1.1.1k-5.el9_8.3 will resolve the issue.
If immediate updates are not possible, consider disabling features that rely on the affected libraries 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 vulnerabilities using the Vulert playground without any signup.
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