CVE-2022-50819 is a deferred vulnerability found in the Linux kernel, specifically related to the udmabuf component. This vulnerability allows the system to encounter a crash when userspace attempts to map a dmabuf and the creation of the sg table fails, potentially leading to a general protection fault. The severity level of this vulnerability has not been officially scored, but organizations should be aware of its implications.
According to the details provided, if the sg table creation fails due to insufficient memory (OOM), the ubuf->sg variable needs to be set to NULL. Failure to do so will result in the system attempting to free an invalid sg table during the closing of the dmabuf file descriptor, which can lead to system instability.
The urgency for defenders is low, as the vulnerability is marked as deferred and does not currently have a known exploit. However, organizations should continue to monitor for updates and patches that address this issue, particularly as it involves kernel-level functionality that could impact system stability.
Organizations should also ensure they are running the latest versions of the Linux kernel and remain vigilant about potential updates that may mitigate this vulnerability.
Vulnerability Details
The official description of CVE-2022-50819 highlights a significant oversight in the Linux kernel's handling of the udmabuf module. If the creation of an sg table fails during userspace mapping, it is critical to set ubuf->sg to NULL. Failure to implement this precaution results in a crash when the dmabuf fd is closed, as the system erroneously attempts to free an invalid sg table.
Details of the crash reported by syzbot indicate a general protection fault likely caused by a non-canonical address. This indicates a significant issue that could lead to system instability if not addressed.
Technical Analysis
Root cause analysis indicates that the failure to set ubuf->sg to NULL when the sg table creation fails can lead to attempts to dereference a null pointer. This is compounded by the fact that the vulnerability appears when userspace processes attempt to map dmabufs under low-memory conditions.
The attack vector is classified as unknown. The attack complexity is low, given that the issue arises under typical operational conditions when memory is constrained. Privileges required are none, as any userspace process can trigger the issue. User interaction is not required, as the vulnerability can be exploited automatically when certain memory conditions are met.
Risk & Impact Analysis
Risk to organizations includes potential system crashes and instability in environments that rely on the Linux kernel and utilize the udmabuf module. The blast radius could be significant in production scenarios, particularly in systems with constrained memory resources.
Due to the low EPSS score of 0.00027, the vulnerability is currently assessed as having a low likelihood of exploitation. However, organizations should still prioritize monitoring and readying their systems for potential updates or patches.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
All versions prior to the vendor patch are affected. Organizations should ensure they are running the most recent and secure versions of the Linux kernel.
Mitigation & Remediation
Organizations should stay informed about updates and patches related to this vulnerability. Regular system updates and monitoring for kernel vulnerabilities are essential for maintaining system security. For more comprehensive security assessments, organizations may consider engaging in application security assessments to identify and remediate underlying issues.
Detection Guidance
Monitoring for system crashes and kernel panics can provide indicators of this vulnerability being triggered. Organizations should log instances of general protection faults and examine stack traces for references to udmabuf and sg table manipulations.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2022-50819 lies in its representation of systemic issues within the Linux kernel's memory management. It highlights the importance of proper error handling in kernel modules to prevent crashes that can destabilize systems. Security teams should prioritize establishing robust error management practices to mitigate similar vulnerabilities in the future.
For further insights on improving security posture, organizations can explore our vulnerability management program and consider adopting penetration testing methodologies to identify and remediate vulnerabilities before they can be exploited.
Additionally, understanding the trends in kernel vulnerabilities can inform better defensive strategies. For more details on current trends, refer to our vulnerability exposure trends report.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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