CVE-2022-49289 in Linux
Summary
by MITRE • 02/26/2025
In the Linux kernel, the following vulnerability has been resolved:
uaccess: fix integer overflow on access_ok()
Three architectures check the end of a user access against the address limit without taking a possible overflow into account. Passing a negative length or another overflow in here returns success when it should not.
Use the most common correct implementation here, which optimizes for a constant 'size' argument, and turns the common case into a single comparison.
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Analysis
by VulDB Data Team • 02/16/2026
The vulnerability CVE-2022-49289 represents a critical integer overflow flaw within the Linux kernel's user access validation mechanism, specifically affecting the access_ok() function implementation across multiple architectures. This issue resides in the kernel's memory management subsystem where the system validates whether user-space memory accesses are within acceptable bounds before permitting operations. The vulnerability manifests when the kernel checks user access limits against address boundaries without properly accounting for potential integer overflow conditions that could occur during the validation process.
The technical flaw stems from three different processor architectures implementing the access_ok() function in a manner that fails to consider overflow scenarios when evaluating user memory access boundaries. When a negative length parameter or other overflow conditions are passed to this validation routine, the system incorrectly returns a success status instead of properly rejecting the invalid access attempt. This misbehavior occurs because the implementation does not perform proper overflow checking before comparing user access limits against address boundaries, creating a scenario where maliciously crafted inputs could bypass critical security checks. The vulnerability affects the kernel's ability to properly enforce memory access controls, potentially allowing unauthorized memory access patterns that should be blocked by the kernel's security mechanisms.
The operational impact of CVE-2022-49289 extends beyond simple privilege escalation scenarios as it represents a fundamental breakdown in kernel memory protection mechanisms that could enable various attack vectors. An attacker could potentially exploit this vulnerability to access memory regions that should be restricted, leading to information disclosure, privilege escalation, or system stability compromise. The flaw is particularly concerning because it affects multiple architectures simultaneously, suggesting a widespread implementation issue that would impact numerous Linux deployments across different hardware platforms. This vulnerability directly violates the kernel's fundamental security principle of enforcing strict memory access controls and could enable attackers to bypass critical security boundaries that protect kernel memory spaces from user-space processes.
The fix implemented for CVE-2022-49289 adopts the most commonly accepted and robust approach to address the integer overflow issue, specifically optimizing for constant size arguments while ensuring the common case requires only a single comparison operation. This solution addresses the core problem by implementing proper overflow detection before performing access boundary checks, thereby preventing the incorrect success return that occurred when negative values or overflow conditions were encountered. The mitigation strategy aligns with established security practices for kernel memory management and follows the principle of least privilege enforcement that is fundamental to operating system security. This approach reduces complexity while maintaining performance characteristics for normal operations, ensuring that the fix does not introduce significant overhead for legitimate kernel functionality.
This vulnerability maps to CWE-191, Integer Underflow (Wrap or Wraparound), and CWE-190, Integer Overflow, as it involves improper handling of arithmetic operations that can result in overflow conditions affecting security checks. The flaw could potentially be leveraged as part of broader attack chains within the MITRE ATT&CK framework, particularly under the privilege escalation and defense evasion techniques where attackers seek to bypass kernel security mechanisms. The vulnerability highlights the importance of proper integer arithmetic handling in kernel space and demonstrates how seemingly simple validation functions can contain critical security flaws that undermine fundamental system protections. The resolution represents a standard security fix pattern that emphasizes robust input validation and proper arithmetic overflow handling in kernel-level memory management functions.