Bug 2546368 (CVE-2026-98171) - CVE-2026-98171 kernel: kernel: Use-after-free in SMB client via malformed compound encrypted frames
Summary: CVE-2026-98171 kernel: kernel: Use-after-free in SMB client via malformed com...
Keywords:
Status: NEW
Alias: CVE-2026-98171
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-10-06 09:07 UTC by OSIDB Bzimport
Modified: 2026-11-02 15:52 UTC (History)
17 users (show)

Fixed In Version:
Clone Of:
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Description OSIDB Bzimport 2026-10-06 09:07:09 UTC
In the Linux kernel, the following vulnerability has been resolved:

smb: client: fix next_buffer UAF and NextCommand bounds in compound PDUs

Fix several related bounds checking and pointer lifecycle issues in
receive_encrypted_standard()'s handling of compound encrypted frames:

- Clear next_buffer after assigning it to server->bigbuf. A stale
  next_buffer pointer can lead to a use-after-free on subsequent
  error paths.
- Update pdu_length to the decrypted plaintext size (buf_size). Using
  the pre-decryption length allows NextCommand to point into stale
  ciphertext residue.
- Reject next_cmd values smaller than MID_HEADER_SIZE(server).
- Fix an integer overflow in the upper bound check by verifying
  pdu_length - next_cmd < MID_HEADER_SIZE(server), ensuring the
  trailing slice is large enough for a header.


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