cve/2024/CVE-2024-56558.md

### [CVE-2024-56558](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-56558)
![](https://img.shields.io/static/v1?label=Product&message=Linux&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=3.17%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Version&message=bf18f163e89c52e09c96534db45c4274273a0b34%20&color=brightgreen)
![](https://img.shields.io/static/v1?label=Vulnerability&message=n%2Fa&color=blue)

### Description

In the Linux kernel, the following vulnerability has been resolved:nfsd: make sure exp active before svc_export_showThe function `e_show` was called with protection from RCU. This onlyensures that `exp` will not be freed. Therefore, the reference count for`exp` can drop to zero, which will trigger a refcount use-after-freewarning 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:25refcount_warn_saturate+0xb1/0x120CPU: 3 UID: 0 PID: 819 Comm: cat Not tainted 6.12.0-rc3+ #1Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS1.16.1-2.fc37 04/01/2014RIP: 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

### POC

#### Reference
No PoCs from references.

#### Github
- https://github.com/ARPSyndicate/cve-scores
- https://github.com/cku-heise/euvd-api-doc
- https://github.com/w4zu/Debian_security