What is CVE-2026-64383?

CVE-2026-64383 is a critical-severity vulnerability in Linux, classified under Double Free. CVSS score: 9.8/10. Published 2026-07-25.

How severe is CVE-2026-64383?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Double Free in Linux

CVE-2026-64383

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix double-free in SMB2_flush() replay SMB2_flush() keeps its response buffer bookkeeping across replay attempts. If a replayable flush response is received and the retry then fails before cifs_send_recv() stores a replacement response, flush_exit will free the stale response pointer a second time. Reinitialize resp_buftype and rsp_iov at the top of the replay loop so cleanup only acts on response state produced by the current attempt. This fixes a double-free without changing replay handling for successful requests.

Vulnerability class: Double Free

EPSS: 0.005 (38.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Linux — versions 7.2-rc1, 6.6.145, 433042a91f9373241307725b52de573933ffedbf
Linux Linux_kernel — versions 6.8

Weakness classification (CWE)

CWE-415 — Double Free

References

416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Patch)
416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Patch)
416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Patch)
416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Patch)
416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Patch)

Frequently asked questions

What is CVE-2026-64383?: CVE-2026-64383 is a critical-severity vulnerability in Linux, classified under Double Free. CVSS score: 9.8/10. Published 2026-07-25.
How severe is CVE-2026-64383?: Critical severity. CVSS v3 base score is 9.8 out of 10.