CVE-2023-52757: smb: client: fix potential deadlock when releasing mids

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-05-21 · updated 2026-06-17
Weakness: CWE-416

Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix potential deadlock when releasing mids All release_mid() callers seem to hold a reference of @mid so there is no need to call kref_put(&mid->refcount, __release_mid) under @server->mid_lock spinlock. If they don't, then an use-after-free bug would have occurred anyways. By getting rid of such spinlock also fixes a potential deadlock as shown below CPU 0 CPU 1 ------------------------------------------------------------------ cifs_demultiplex_thread() cifs_debug_data_proc_show() release_mid() spin_lock(&server->mid_lock); spin_lock(&cifs_tcp_ses_lock) spin_lock(&server->mid_lock) __release_mid() smb2_find_smb_tcon() spin_lock(&cifs_tcp_ses_lock) *deadlock*

Affected products

Debian Linux: 11.0
Linux kernel: before 5.10.237; from 5.11 before 5.15.181; from 5.16 before 6.1.64; from 6.2 before 6.5.13; from 6.6 before 6.6.3 — fixed in 5.10.237, 5.15.181, 6.1.64, 6.5.13, 6.6.3

How to fix

Upgrade to a fixed version: Linux kernel 5.10.237, 5.15.181, 6.1.64, 6.5.13. Check the vendor advisory for mitigations.

References

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