{"cve":"CVE-2024-41070","nvd":{"published":"2024-07-29T15:15:14.787","modified":"2026-08-04T11:19:26.160","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: PPC: Book3S HV: Prevent UAF in kvm_spapr_tce_attach_iommu_group()\n\nAl reported a possible use-after-free (UAF) in kvm_spapr_tce_attach_iommu_group().\n\nIt looks up `stt` from tablefd, but then continues to use it after doing\nfdput() on the returned fd. After the fdput() the tablefd is free to be\nclosed by another thread. The close calls kvm_spapr_tce_release() and\nthen release_spapr_tce_table() (via call_rcu()) which frees `stt`.\n\nAlthough there are calls to rcu_read_lock() in\nkvm_spapr_tce_attach_iommu_group() they are not sufficient to prevent\nthe UAF, because `stt` is used outside the locked regions.\n\nWith an artifcial delay after the fdput() and a userspace program which\ntriggers the race, KASAN detects the UAF:\n\n  BUG: KASAN: slab-use-after-free in kvm_spapr_tce_attach_iommu_group+0x298/0x720 [kvm]\n  Read of size 4 at addr c000200027552c30 by task kvm-vfio/2505\n  CPU: 54 PID: 2505 Comm: kvm-vfio Not tainted 6.10.0-rc3-next-20240612-dirty #1\n  Hardware name: 8335-GTH POWER9 0x4e1202 opal:skiboot-v6.5.3-35-g1851b2a06 PowerNV\n  Call Trace:\n    dump_stack_lvl+0xb4/0x108 (unreliable)\n    print_report+0x2b4/0x6ec\n    kasan_report+0x118/0x2b0\n    __asan_load4+0xb8/0xd0\n    kvm_spapr_tce_attach_iommu_group+0x298/0x720 [kvm]\n    kvm_vfio_set_attr+0x524/0xac0 [kvm]\n    kvm_device_ioctl+0x144/0x240 [kvm]\n    sys_ioctl+0x62c/0x1810\n    system_call_exception+0x190/0x440\n    system_call_vectored_common+0x15c/0x2ec\n  ...\n  Freed by task 0:\n   ...\n   kfree+0xec/0x3e0\n   release_spapr_tce_table+0xd4/0x11c [kvm]\n   rcu_core+0x568/0x16a0\n   handle_softirqs+0x23c/0x920\n   do_softirq_own_stack+0x6c/0x90\n   do_softirq_own_stack+0x58/0x90\n   __irq_exit_rcu+0x218/0x2d0\n   irq_exit+0x30/0x80\n   arch_local_irq_restore+0x128/0x230\n   arch_local_irq_enable+0x1c/0x30\n   cpuidle_enter_state+0x134/0x5cc\n   cpuidle_enter+0x6c/0xb0\n   call_cpuidle+0x7c/0x100\n   do_idle+0x394/0x410\n   cpu_startup_entry+0x60/0x70\n   start_secondary+0x3fc/0x410\n   start_secondary_prolog+0x10/0x14\n\nFix it by delaying the fdput() until `stt` is no longer in use, which\nis effectively the entire function. To keep the patch minimal add a call\nto fdput() at each of the existing return paths. Future work can convert\nthe function to goto or __cleanup style cleanup.\n\nWith the fix in place the test case no longer triggers the UAF.","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/4cdf6926f443c84f680213c7aafbe6f91a5fcbc0","https://git.kernel.org/stable/c/5f856023971f97fff74cfaf21b48ec320147b50a","https://git.kernel.org/stable/c/82c7a4cf14aa866f8f7f09e662b02eddc49ee0bf","https://git.kernel.org/stable/c/9975f93c760a32453d7639cf6fcf3f73b4e71ffe","https://git.kernel.org/stable/c/a986fa57fd81a1430e00b3c6cf8a325d6f894a63"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:53:51.317825789+00:00"},"epss":{"cve":"CVE-2024-41070","score":0.0023,"percentile":0.1389,"date":"2026-10-31"},"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."]}