Linux kernel vulnerability in CIFS/SMB client is widely deployed; remote-triggerable kernel use-after-free can crash or enable RCE, impacting many servers and endpoints.
CVE-2026-98261
Use-after-free in Linux CIFS/SMB handling enabling kernel crash or possible RCE
Is CVE-2026-98261 being exploited?
Not confirmed. CVE-2026-98261 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.
How severe is CVE-2026-98261?
CVE-2026-98261 is rated High with a CVSS score of 8.1. 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-2026-98261?
Yes. A fix has been recorded for CVE-2026-98261. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-98261 affect?
CVE-2026-98261 affects Linux kernel (CIFS/SMB client), Linux distributions with affected kernels, Systems using SMB client stacks. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-98261?
Install kernel updates with CIFS fix ASAP; block or restrict untrusted SMB servers until patched.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote SMB server can trigger a kernel use-after-free in CIFS, causing system crash or potential kernel-level code execution.
Immediate action required
- affected>= 50e8363ecc85da49764781da90ebffe1a657b370 and < 0338489960ddad6368bce55e8adbc176c523093d
- affected>= f591062bdbf4742b7f1622173017f19e927057b0 and < edd52eae5fcfb8433b6bb0e7cd98db438fe01227
- affected>= f591062bdbf4742b7f1622173017f19e927057b0 and < fcc0a935bb6e37ecbf7e4335061309f896f35780
- affected>= f591062bdbf4742b7f1622173017f19e927057b0 and < 7a1b27780b113583a94256d58dabfe7c0d9286e7
- affected>= f591062bdbf4742b7f1622173017f19e927057b0 and < 717e0a25036b6c92cecace30913b2d874a4c22b8
- affectedd61ba1d71ea6039eca7ada870bf3f0c3c8fc12e4
- affected>= 6.6.15 and < 6.6.158
- affected>= 6.7.3 and < 6.8
- affected6.8
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.