A flaw in the Linux kernel causes the jiffies clocksource to be used before it is fully registered. The uninitialized field max_delta_raw remains zero, so the time read is clamped to zero and the system clock does not advance. This results in a long boot delay or a complete halt of the timekeeping subsystem, which can manifest as a denial of service during startup, especially in virtualized environments such as XEN HVM.

All Linux kernel implementations are potentially affected. The flaw exists in the core timekeeping code and is not limited to a specific distribution or kernel version, so any system running a Linux kernel that has not applied the fix is vulnerable.

The vulnerability has no publicly available exploitation code and is not listed in the CISA KEV catalog. The EPSS score is < 1% and the CVSS score is 5.5, indicating moderate severity. The defect can lead to a denial of service during boot. Based on the description, it is inferred that exploitation would require triggering the code path during early boot, implying the attacker would need control over the boot process or kernel execution. This inference is based on the nature of the bug; the CVE does not explicitly state attacker capabilities.