Tony Luck

**Name of the Vulnerable Software and Affected Versions** Linux kernel (affected versions not specified) **Description** A rare kernel panic scenario can occur due to an erratum on fast string copy instructions in the Linux kernel. This issue happens when an uncorrected error is present in the first cache line of a page, and the kernel executes page copy from the page immediately before that page. The fast string copy instructions could consume an uncorrectable memory error and raise a Machine Check Exception (MCE). This erratum is confirmed by Intel to only apply to Skylake, Cascade Lake, and Cooper Lake generations. **Recommendations** To mitigate this issue, consider disabling fast string copy by clearing bit 0 of MSR IA32 MISC ENABLE, although this may result in a permanent performance impact. Alternatively, the kernel can be modified to directly return from the MCE handler, which will prevent the kernel panic but may still result in performance degradation due to the disabling of fast string copy on the affected hyper thread. At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Name of the Vulnerable Software and Affected Versions: Linux kernel versions prior to 2.6.26 Description: The issue is related to the ia64 subsystem in the Linux kernel, which allows local users to cause a denial of service. This can be achieved through a crafted application that exploits the mishandling of invalid Register Stack Engine (RSE) state, leading to stack consumption and a system crash. Recommendations: For versions prior to 2.6.26, update to version 2.6.26 or later to resolve the issue.

**Name of the Vulnerable Software and Affected Versions** Linux kernel versions prior to 2.6.39 **Description** The issue allows local users to cause a denial of service via vectors that trigger an m start error in the m stop function. **Recommendations** For versions prior to 2.6.39, update to version 2.6.39 or later to resolve the issue.