Kernel-level CephFS vulnerability affects Linux systems using Ceph clients; high CVSS (9.1) and potential to disrupt storage/endpoints across organizations.
CVE-2026-89650
Linux kernel CephFS client OOB read via crafted MDS map
Is CVE-2026-89650 being exploited?
Not confirmed. CVE-2026-89650 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 0.51% probability of exploitation in the next 30 days.
How severe is CVE-2026-89650?
CVE-2026-89650 is rated Critical with a CVSS score of 9.1. 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-2026-89650?
Yes. A fix has been recorded for CVE-2026-89650. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-89650 affect?
CVE-2026-89650 affects Linux kernel (CephFS client - mdsmap decoder), Systems running CephFS clients connected to Ceph monitors. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-89650?
Apply kernel updates with the Ceph mdsmap fix and restrict/verify Ceph monitors.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Malicious/compromised Ceph monitor can trigger an out-of-bounds kernel read in CephFS clients, risking crashes or kernel memory corruption.
Immediate action required
- affected>= d463a43d69f4af85887671d76182437775fd1631 and < 0c4bcc3ba7291d383b82ce1c2fe324f69a42da2d
- affected>= d463a43d69f4af85887671d76182437775fd1631 and < 55a06b32438c222765138727d0a8164b103e8f0d
- affected>= d463a43d69f4af85887671d76182437775fd1631 and < eb3e1a1cb1634c76d59c5a9cb1a026fc69d40911
- affected>= d463a43d69f4af85887671d76182437775fd1631 and < 3bf7dba8dba9a05774b846affec61a3624ddba38
- affected>= d463a43d69f4af85887671d76182437775fd1631 and < 58c2d3e954c13694ef6e820a5e9456461bb9e7df
- affected>= d463a43d69f4af85887671d76182437775fd1631 and < 332c444f4dc6fa1e8b8637c9e82d29e97f768656
- affected>= d463a43d69f4af85887671d76182437775fd1631 and < a3eb169ee297aa99670ba927c659990bd1e453f3
- affected4.7
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.