In the Linux kernel, a flaw was identified in the md/raid1 and raid10 drivers where certain I/O flags such as REQ_IDLE, REQ_META, and REQ_NOWAIT were ignored. This oversight caused write operations to be throttled by block write‑back throttling (wbt), leading to poor write performance and, in some cases, incorrect timing behavior. The result is a moderate degradation in system performance and a risk that blocked or delayed writes may not complete as expected, potentially affecting application reliability.

All versions of the Linux kernel that include the md/raid1 and raid10 subsystems are subject to this issue, as the flaw has existed since the introduction of blk-wbt. The specific product is the open‑source Linux kernel; no further version specificity is available from the CNA data.

The CVSS score of 5.5 reflects medium severity, and the EPSS score of less than 1% indicates a very low probability of exploitation. The vulnerability is not listed in CISA’s KEV catalog. It requires local access to the kernel, typically involving a user or process interacting with mdraid devices, and exploits the kernel’s handling of I/O flags. There is no known remote exploitation vector, so the risk is primarily limited to environments where malicious users can influence I/O behavior on the host.