Critical Vulnerability in Linux Kernel: CVE-2025-40019 - ESSIV Decryption Check Bypass
Summary
DEBIAN-CVE-2025-40019: In the Linux kernel, the following vulnerability has been resolved: crypto: essiv - Check ssize for decryption and in-place encryption Move the ssize check to the start in essiv_aead_crypt so that it's also checked for d... Affects linux versions 5.10.103-1 – 6.9.9-1. No fix is published. How to fix ↓
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Background
The Linux kernel is the core component of the Linux operating system, responsible for managing hardware resources and providing essential services to software applications. It is widely used across various platforms, from servers to embedded systems. The kernel's security is paramount, as vulnerabilities can lead to unauthorized access or system instability. This specific vulnerability affects the ESSIV (Encrypted Salt-Sector Initialization Vector) functionality within the kernel's cryptographic module, which is crucial for secure data encryption and decryption.
Vulnerability Detail
CVE-2025-40019 is a vulnerability in the Linux kernel's ESSIV implementation that allows for a bypass of size checks during decryption and in-place encryption operations. This flaw could potentially lead to unauthorized data access or corruption, as the absence of proper size validation may allow attackers to manipulate encrypted data without detection. The vulnerability originates from an oversight in the implementation of the ESSIV algorithm, where the ssize check was not adequately enforced for all operations, particularly decryption.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
As a temporary workaround, users can avoid using the ESSIV functionality for encryption and decryption until the kernel is updated. This can be done by configuring applications to use alternative cryptographic methods that do not rely on ESSIV.
Conclusion
CVE-2025-40019 is a critical vulnerability in the Linux kernel that poses significant risks to data security. Users are strongly advised to update their systems to the latest patched version of the Linux kernel to mitigate these risks. Additionally, utilizing tools like Vulert can help monitor and alert for such vulnerabilities in real-time.
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FAQ
CVE-2025-40019 is a vulnerability in the Linux kernel that affects the ESSIV cryptographic implementation, allowing for potential bypass of security checks.
If exploited, this vulnerability could allow unauthorized access to encrypted data or lead to data corruption, compromising system integrity.
The vulnerability affects multiple versions of the Linux kernel across Debian distributions, including Debian 11, 12, 13, and 14.
You can use Vulert, a tool that monitors open-source vulnerabilities in your software. By simply uploading your manifest file, such as package-lock.json, you can check for vulnerabilities without needing to install any software.
Yes, you can temporarily avoid using the ESSIV functionality for encryption and decryption until the kernel is updated.
References
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