{"cve":"CVE-2024-56558","nvd":{"published":"2024-12-27T15:15:14.633","modified":"2026-06-17T08:12:23.337","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: make sure exp active before svc_export_show\n\nThe function `e_show` was called with protection from RCU. This only\nensures that `exp` will not be freed. Therefore, the reference count for\n`exp` can drop to zero, which will trigger a refcount use-after-free\nwarning when `exp_get` is called. To resolve this issue, use\n`cache_get_rcu` to ensure that `exp` remains active.\n\n------------[ cut here ]------------\nrefcount_t: addition on 0; use-after-free.\nWARNING: CPU: 3 PID: 819 at lib/refcount.c:25\nrefcount_warn_saturate+0xb1/0x120\nCPU: 3 UID: 0 PID: 819 Comm: cat Not tainted 6.12.0-rc3+ #1\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS\n1.16.1-2.fc37 04/01/2014\nRIP: 0010:refcount_warn_saturate+0xb1/0x120\n...\nCall Trace:\n <TASK>\n e_show+0x20b/0x230 [nfsd]\n seq_read_iter+0x589/0x770\n seq_read+0x1e5/0x270\n vfs_read+0x125/0x530\n ksys_read+0xc1/0x160\n do_syscall_64+0x5f/0x170\n entry_SYSCALL_64_after_hwframe+0x76/0x7e","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8},"cwes":["CWE-416"],"references":["https://git.kernel.org/stable/c/1cecfdbc6bfc89c516d286884c7f29267b95de2b","https://git.kernel.org/stable/c/6cefcadd34e3c71c81ea64b899a0daa86314a51a","https://git.kernel.org/stable/c/7365d1f8de63cffdbbaa2287ce0205438e1a922f","https://git.kernel.org/stable/c/7d8f7816bebcd2e7400bb4d786eccb8f33c9f9ec","https://git.kernel.org/stable/c/7fd29d284b55c2274f7a748e6c5f25b4758b8da5"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:57:56.913276502+00:00"},"epss":{"cve":"CVE-2024-56558","score":0.00243,"percentile":0.15582,"date":"2026-11-01"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}