Linux kernel ksmbd bug affects widely deployed OS kernels and SMB servers; can disrupt servers and enable kernel compromise, warranting broad IT notice.
CVE-2026-98870
Linux kernel ksmbd use-after-free in session teardown may allow crash or kernel compromise.
Is CVE-2026-98870 being exploited?
Not confirmed. CVE-2026-98870 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 0.54% probability of exploitation in the next 30 days.
How severe is CVE-2026-98870?
CVE-2026-98870 is rated High with a CVSS score of 8.8. 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-2026-98870?
Yes. A fix has been recorded for CVE-2026-98870. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-98870 affect?
CVE-2026-98870 affects Linux kernel (ksmbd SMB server), Linux distributions using in-kernel ksmbd. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-98870?
Install kernel updates with ksmbd patch and restart SMB services.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote authenticated SMB client can trigger a kernel use-after-free causing DoS or possible kernel RCE/privilege escalation.
Patch when possible
- affected>= b1b6ed903a6e2b3505a48706bcd499b447ef9e44 and < f8200bb4994e65a2e5c5b314789eeae39078619d
- affected>= 47b018dba6ec7ebf403fd2d1e713bc7acc9bbb23 and < 9cd6d714d3ca0cff296542dc989696884e41970f
- affected>= 9ef4dfd5edbd02f4bf10cd420a30896093d98a67 and < b145f9b56c87f9c23ad5464ab0844dbc1de12b36
- affected>= 5a5b0b7a01fe19b383b3c046546b5ae30c1a7d71 and < a15cae16f4432a5ad919ee633e31b07178492955
- affected>= faf8578c77f3d846aca9cd882c293e03eafcc6df and < b10665730fbf6b5e45fe422badcbbc3f0df96ef5
- affectede632f21a8bc0c59abc4960482836ac3782db93c0
- affected>= 5.15.222 and < 5.16
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.