Kernel-level flaw affecting widely deployed Linux kernel with libceph; could enable memory disclosure/crash via crafted frames.
CVE-2026-43406
Kernel libceph OOB read via crafted message frame.
Is CVE-2026-43406 being exploited?
Not confirmed. CVE-2026-43406 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 0.50% probability of exploitation in the next 30 days.
How severe is CVE-2026-43406?
CVE-2026-43406 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-2026-43406?
Yes. A fix has been recorded for CVE-2026-43406. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-43406 affect?
CVE-2026-43406 affects Linux kernel (libceph). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-43406?
Apply latest kernel update with libceph fix
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Out-of-bounds read in process_message_header when parsing malicious Ceph frames; kernel memory disclosure or crash possible.
Patch when possible
- affected>= cd1a677cad994021b19665ed476aea63f5d54f31 and < 76ccf21a12c5f6d6790bc32c7da82446d877b2f4
- affected>= cd1a677cad994021b19665ed476aea63f5d54f31 and < 75582aaa580c11aed4c7731cad6b068b700e7efb
- affected>= cd1a677cad994021b19665ed476aea63f5d54f31 and < 50156622eb0888e62541d715a98584480a1bc7cb
- affected>= cd1a677cad994021b19665ed476aea63f5d54f31 and < dbd857a9e1e33ea71eaf3e211877027e533770d1
- affected>= cd1a677cad994021b19665ed476aea63f5d54f31 and < 69fe5af33fa3806f398d21c081d73c66e5523bc2
- affected>= cd1a677cad994021b19665ed476aea63f5d54f31 and < 035867ae6f18df0aeedb2a57a5b74091bd4e3fe8
- affected>= cd1a677cad994021b19665ed476aea63f5d54f31 and < 69fb5d91bba44ecf7eb80530b85fa4fb028921d5
- affected5.11
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.