CVE-2026-46045: md/md-llbitmap: skip reading rdevs that are not in_sync

Vulnerability summary

CVE-2026-46045 is a high (CVSS 7.8) Out-of-bounds Write vulnerability in linux. EPSS estimates a 0.13% chance of exploitation in the next 30 days, higher than 2.4% of scored vulnerabilities.

Timeline

1. 27-05-2026
   PublishedVulnerability first disclosed.
2. 14-06-2026
   Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: md/md-llbitmap: skip reading rdevs that are not in_sync When reading bitmap pages from member disks, the code iterates through all rdevs and attempts to read from the first available one. However, it only checks for raid_disk assignment and Faulty flag, missing the In_sync flag check. This can cause bitmap data to be read from spare disks that are still being rebuilt and don't have valid bitmap information yet. Reading stale or uninitialized bitmap data from such disks can lead to incorrect dirty bit tracking, potentially causing data corruption during recovery or normal operation. Add the In_sync flag check to ensure bitmap pages are only read from fully synchronized member disks that have valid bitmap data.

• CWE-787Out-of-bounds WriteThe product writes data past the end, or before the beginning, of the intended buffer.