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Unrated severityNVD Advisory· Published Dec 27, 2024· Updated Nov 3, 2025

nfsd: make sure exp active before svc_export_show

CVE-2024-56558

Description

In the Linux kernel, the following vulnerability has been resolved:

nfsd: make sure exp active before svc_export_show

The function e_show was called with protection from RCU. This only ensures that exp will not be freed. Therefore, the reference count for exp can drop to zero, which will trigger a refcount use-after-free warning when exp_get is called. To resolve this issue, use cache_get_rcu to ensure that exp remains active.

------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 3 PID: 819 at lib/refcount.c:25 refcount_warn_saturate+0xb1/0x120 CPU: 3 UID: 0 PID: 819 Comm: cat Not tainted 6.12.0-rc3+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014 RIP: 0010:refcount_warn_saturate+0xb1/0x120 ... Call Trace:

e_show+0x20b/0x230 [nfsd] seq_read_iter+0x589/0x770 seq_read+0x1e5/0x270 vfs_read+0x125/0x530 ksys_read+0xc1/0x160 do_syscall_64+0x5f/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Affected products

237

Patches

0

No patches discovered yet.

Vulnerability mechanics

AI mechanics synthesis has not run for this CVE yet.

References

7

News mentions

0

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