Moderate Security Vulnerability in libkcapi: IV Reuse and Memory Corruption Issues
Summary
RLSA-2026:67265: Moderate: libkcapi security, bug fix, and enhancement update. Affects libkcapi versions < 0:1.4.0-3.el9_8. Fixed in 0:1.4.0-3.el9_8. How to fix ↓
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Background
libkcapi is a library that allows user-space applications to access the Linux kernel crypto API. It simplifies the use of the netlink interface, enabling developers to interact with cryptographic functions without delving into low-level details. The library does not implement cipher algorithms itself; instead, it forwards requests to the kernel for processing. This design allows unprivileged processes to utilize the kernel's cryptographic capabilities, which can lead to security vulnerabilities if not properly managed.
Vulnerability Detail
The vulnerabilities in libkcapi stem from several issues: IV reuse in one-shot symmetric cipher chunking can lead to cipher state resets across chunk boundaries (CVE-2026-71225). Additionally, memory corruption can occur due to uncanceled AIO requests on error in the one-shot AIO path (CVE-2026-71226). Lastly, an infinite loop denial of service can arise in the _kcapi_aio_read_all() function due to unhandled io_getevents() timeout returns (CVE-2026-71227). These vulnerabilities could allow attackers to manipulate cryptographic operations, potentially leading to unauthorized access or denial of service.
How To Fix
Minimum fixed version
0:1.4.0-3.el9_8
This is the first release that contains the fix.
sudo dnf update libkcapiTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
Currently, there are no specific workarounds mentioned for these vulnerabilities. It is advisable to apply the patch as soon as possible to secure the system.
Conclusion
The vulnerabilities in libkcapi present significant risks, including potential unauthorized access and denial of service. It is crucial for users to update to the latest patched version to mitigate these risks effectively. Regular monitoring for vulnerabilities using tools like Vulert can help maintain the security of your applications.
See every vulnerability recorded for libkcapi →
FAQ
libkcapi is a library that provides user-space access to the Linux kernel crypto API, allowing developers to utilize cryptographic functions without dealing with low-level netlink interface complexities.
The main vulnerabilities include IV reuse leading to cipher state resets, memory corruption from uncanceled AIO requests, and an infinite loop denial of service due to unhandled timeout returns.
You can use Vulert, which monitors and alerts for open-source vulnerabilities in your software. By utilizing the Vulert playground, you can check if your application is affected without requiring access to the code or installation.
The CVSS score for this vulnerability is 7.3, indicating a moderate severity level.
You can update libkcapi by running the command 'sudo dnf update libkcapi' in your terminal. Ensure that you are updating to version 0:1.4.0-3.el9_8 or later.
References
Related vulnerabilities
Recent vulnerabilities recorded for libkcapi.
