Linux kernel is ubiquitous; bug causes silent data corruption on md/raid10, risking widespread data loss on servers and storage.
CVE-2026-89558
Kernel md/raid10 bug can cause silent data corruption during mirror recovery.
Is CVE-2026-89558 being exploited?
Not confirmed. CVE-2026-89558 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.63% probability of exploitation in the next 30 days.
How severe is CVE-2026-89558?
CVE-2026-89558 is rated Critical with a CVSS score of 9.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-89558?
Yes. A fix has been recorded for CVE-2026-89558. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-89558 affect?
CVE-2026-89558 affects Linux kernel (md/raid10), Systems using mdadm RAID10 with internal bitmap, Servers and storage hosts running affected kernels. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-89558?
Apply vendor kernel updates; run mdadm verify/scrub; rebuild arrays if corruption suspected.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Silent data corruption: re-added RAID10 mirror can be marked In_sync with stale data, causing undetected data loss during recovery.
Immediate action required
- affected>= fe6a19d40ceb44281905485f56dda715e3214e0e and < 9bb8da6ecb330a5b1ac9b96f1e55f134a7aef1d4
- affected>= fe6a19d40ceb44281905485f56dda715e3214e0e and < 0efabe6229dc683dbf6eeebd0f9fddc7971ed420
- affected>= fe6a19d40ceb44281905485f56dda715e3214e0e and < 00449d752bee9c8787f42ea1bf533a9fb17f9b6b
- affected>= fe6a19d40ceb44281905485f56dda715e3214e0e and < 47f1441b281decde6954a2fa82b4131637d685ac
- affected6.12
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.