CVE-2024-56558

nfsd: make sure exp active before svc_export_show

State: Published
Severity: 7.8 High
Published: Dec 27, 2024
Updated: Aug 5, 2026
Reserved: Dec 27, 2024

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: <TASK> 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

Scores

CVSS	Score	Vector	Source
3.1	7.8 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H	Linux
3.1	7.8 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H	CISA-ADP

Weaknesses

CWE-416 Use After Free

Affected Products

Product	Versions
LinuxLinux	bf18f163e89c52e09c96534db45c4274273a0b34 to before e2fa0d0e327279a8defb87b263cd0bf288fd9261Affected bf18f163e89c52e09c96534db45c4274273a0b34 to before 7fd29d284b55c2274f7a748e6c5f25b4758b8da5Affected bf18f163e89c52e09c96534db45c4274273a0b34 to before 6cefcadd34e3c71c81ea64b899a0daa86314a51aAffected bf18f163e89c52e09c96534db45c4274273a0b34 to before 7d8f7816bebcd2e7400bb4d786eccb8f33c9f9ecAffected bf18f163e89c52e09c96534db45c4274273a0b34 to before 1cecfdbc6bfc89c516d286884c7f29267b95de2bAffected bf18f163e89c52e09c96534db45c4274273a0b34 to before 7365d1f8de63cffdbbaa2287ce0205438e1a922fAffected bf18f163e89c52e09c96534db45c4274273a0b34 to before be8f982c369c965faffa198b46060f8853e0f1f0Affected
LinuxLinux	3.17Affected before 3.17Not affected 5.4.287 through 5.4.Not affected 5.10.231 through 5.10.Not affected 5.15.174 through 5.15.Not affected 6.1.120 through 6.1.Not affected 6.6.64 through 6.6.Not affected 6.12.4 through 6.12.Not affected 6.13 and laterNot affected

Product

Versions

LinuxLinux

bf18f163e89c52e09c96534db45c4274273a0b34 to before e2fa0d0e327279a8defb87b263cd0bf288fd9261Affected
bf18f163e89c52e09c96534db45c4274273a0b34 to before 7fd29d284b55c2274f7a748e6c5f25b4758b8da5Affected
bf18f163e89c52e09c96534db45c4274273a0b34 to before 6cefcadd34e3c71c81ea64b899a0daa86314a51aAffected
bf18f163e89c52e09c96534db45c4274273a0b34 to before 7d8f7816bebcd2e7400bb4d786eccb8f33c9f9ecAffected
bf18f163e89c52e09c96534db45c4274273a0b34 to before 1cecfdbc6bfc89c516d286884c7f29267b95de2bAffected
bf18f163e89c52e09c96534db45c4274273a0b34 to before 7365d1f8de63cffdbbaa2287ce0205438e1a922fAffected
bf18f163e89c52e09c96534db45c4274273a0b34 to before be8f982c369c965faffa198b46060f8853e0f1f0Affected

LinuxLinux

3.17Affected
before 3.17Not affected
5.4.287 through 5.4.*Not affected
5.10.231 through 5.10.*Not affected
5.15.174 through 5.15.*Not affected
6.1.120 through 6.1.*Not affected
6.6.64 through 6.6.*Not affected
6.12.4 through 6.12.*Not affected
6.13 and laterNot affected

References

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