CVE-2026-64380
Linux kernel SMB client SID parsing bug allows remote crash or memory corruption.
Is CVE-2026-64380 being exploited?
Not confirmed. CVE-2026-64380 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 0.44% probability of exploitation in the next 30 days.
How severe is CVE-2026-64380?
CVE-2026-64380 is rated High with a CVSS score of 8.2. 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-2026-64380?
Yes. A fix has been recorded for CVE-2026-64380. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-64380 affect?
CVE-2026-64380 affects Linux kernel (SMB/CIFS client), Linux distributions using affected kernels. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-64380?
Update Linux kernel to vendor-fixed release; block untrusted SMB servers until patched.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
A malicious SMB server can send crafted POSIX SIDs causing out-of-bounds read leading to client crash (DoS) or memory corruption; potential for RCE in worst case.
Patch when possible
- affected>= 349e13ad30b45998bb9937cfe0b32be6f951976d and < 171605aed68380c2fa75dff9b3a1ed427c50065b
- affected>= 349e13ad30b45998bb9937cfe0b32be6f951976d and < 4213c1208978483021d7d125c131de3985d38f61
- affected>= 349e13ad30b45998bb9937cfe0b32be6f951976d and < 96e889bc1e759c83f25093e8c2f3da31b4973f30
- affected>= 349e13ad30b45998bb9937cfe0b32be6f951976d and < 0de5b8e76847f5de26f364a82c6602c4881c30da
- affected>= 349e13ad30b45998bb9937cfe0b32be6f951976d and < 427eb7eb46425fec845a43e861f3d6e2899cae59
- affected>= 349e13ad30b45998bb9937cfe0b32be6f951976d and < 86c5d470f5d42e61123b2f4b4f0b91f4eee5b980
- affected>= 349e13ad30b45998bb9937cfe0b32be6f951976d and < 46a84715a015cb48e1b9c219dc88c03d8a541ea4
- affected>= 349e13ad30b45998bb9937cfe0b32be6f951976d and < 7ad2bcf2441430bb2e918fb3ef9a90d775a6e422
- affected5.7
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.