UBUNTU-CVE-2026-64136
In the Linux kernel, the following vulnerability has been resolved: smb: client: protect tc_count increment in smb2_find_smb_sess_tcon_unlocked() Commit 96c4af418586 ("cifs: Fix locking usage for tcon fields") refactored cifs code to change cifs_tcp_ses_lock for tc_lock around tc_count changes. There was missing lock around tc_count increment inside smb2_find_smb_sess_tcon_unlocked().
02 / AFFECTED SOFTWARE
Affected packages
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26 explicit affected versions
45 explicit affected versions
37 explicit affected versions
53 explicit affected versions
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11 explicit affected versions
42 explicit affected versions
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5 explicit affected versions
10 explicit affected versions
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11 explicit affected versions
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41 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
In the Linux kernel, the following vulnerability has been resolved: smb: client: protect tc_count increment in smb2_find_smb_sess_tcon_unlocked() Commit 96c4af418586 ("cifs: Fix locking usage for tcon fields") refactored cifs code to change cifs_tcp_ses_lock for tc_lock around tc_count changes. There was missing lock around tc_count increment inside smb2_find_smb_sess_tcon_unlocked().
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/4d8690dace005a38e6dbde9ecce2da3ad85c7c41
- https://ubuntu.com/security/CVE-2026-64136
- https://ubuntu.com/security/notices/USN-8593-1
- https://ubuntu.com/security/notices/USN-8603-1
- https://ubuntu.com/security/notices/USN-8618-1
- https://www.cve.org/CVERecord?id=CVE-2026-64136