CVE-2026-64383

smb: client: fix double-free in SMB2_flush() replay

CRITICAL
9.8
CVSS Score
Published: July 25, 2026 at 08:50 AM UTC
Updated: October 19, 2026 at 09:17 PM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
CRITICAL9.8
Exploit prediction
EPSS 0.5%
SSVC
No known exploit

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

6.13 ≤ v < 6.18.396.19 ≤ v < 7.1.46.6.32 ≤ v < 6.6.1456.8.1 ≤ v < 6.12.96433042a91f9373241307725b52de573933ffedbf4f1fffa2376922f3d1d506e49c0fd445b023a28e6.6.326.86.8 rc26.8 rc36.8 rc46.8 rc56.8 rc66.8 rc7
Vendor states this is fixed in 013a9a3da46c5dabcf18f65ea6a47874ba12a15d (fixed)
Vendor states this is fixed in 3407240cde132a4b72d6429a2625a09a2f78adaf (fixed)
Vendor states this is fixed in 4be31c943a3a27a5a0251dbb8f5cb89059ec3d5a (fixed)
Vendor states this is fixed in 6e27f40b682a5e42a2daae3ce6d96f0e0e16dedb (fixed)
Vendor states this is fixed in 878757163eea684750107a31ea134c103863515d (fixed)
Vendor states this is fixed in 6.12.96 (unaffected)
Vendor states this is fixed in 6.18.39 (unaffected)
Vendor states this is fixed in 6.6.145 (unaffected)
Vendor states this is fixed in 6.8 (unaffected)
Vendor states this is fixed in 7.1.4 (unaffected)
Vendor states this is fixed in 7.2 (unaffected)

SSVC — Action Prioritization

SSVCNo known exploitAutomatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

9.8CRITICALLinux
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-415

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