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CVE PROGRAM SOURCE RECORD9.1 Critical

CVE-2026-68431

ksmbd: validate minimum PDU size for transform requests

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: validate minimum PDU size for transform requests The receive path applies the minimum SMB2 PDU size check only when ProtocolId is SMB2_PROTO_NUMBER. A packet carrying SMB2_TRANSFORM_PROTO_NUM bypasses the check even when the negotiated dialect does not provide transform handling. On an SMB 2.1 connection, a short transform packet therefore reaches init_smb2_rsp_hdr(), which interprets the request as a full SMB2 header and reads beyond the request allocation. The copied fields can then be returned to the unauthenticated client. Compression transforms are converted to ordinary SMB2 messages before protocol validation. After that conversion, validate ordinary SMB2 requests against SMB2_MIN_SUPPORTED_PDU_SIZE and require encryption transform requests to contain both a transform header and an SMB2 header. This rejects truncated requests before work allocation.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • df3a4518aee64f21bcafa891105b468413f27431 to < 22f1aa35b87e471cc31b35b74451f46630863b12affected
  • 543c12c2644e772caa6880662c2a852cfdc5a10c to < 928dda88d0e13fbca381255028f65b244343a4eaaffected
  • 368ba06881c395f1c9a7ba22203cf8d78b4addc0 to < d8e5c5672724b8f3c4c099d2cf60239c996e5424affected
  • 368ba06881c395f1c9a7ba22203cf8d78b4addc0 to < 32e486b70c256d5ef4baa5a2936ade2fea50e8ebaffected
  • 368ba06881c395f1c9a7ba22203cf8d78b4addc0 to < d9e9753dfd43bd27c956578df7804a3c90b80fdcaffected
  • 368ba06881c395f1c9a7ba22203cf8d78b4addc0 to < b62c510f59803f82f9b4c76ead2a56833b2984c7affected
  • 368ba06881c395f1c9a7ba22203cf8d78b4addc0 to < cfc0b8e5080aec87700774e8568765eaa4b7b92baffected
  • e9cb7be2fcbaee9e808b729e92948d38d52e5addaffected
  • 5.15.145 to < 5.15.217affected
  • 6.1.34 to < 6.1.184affected
  • 6.3.8 to < 6.4affected

Linux Linux

Default version status: affected

  • 6.4affected
  • 0 to < 6.4unaffected
  • 5.15.217 to ≤ 5.15.*unaffected
  • 6.1.184 to ≤ 6.1.*unaffected
  • 6.6.153 to ≤ 6.6.*unaffected
  • 6.12.105 to ≤ 6.12.*unaffected
  • 6.18.46 to ≤ 6.18.*unaffected
  • 7.1.6 to ≤ 7.1.*unaffected
  • 7.2 to ≤ *unaffected

References