CVE-2024-56668

CVE-2024-56668 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-401.

Key facts

Description

In the Linux kernel, the following vulnerability has been resolved: iommu/vt-d: Fix qi_batch NULL pointer with nested parent domain The qi_batch is allocated when assigning cache tag for a domain. While for nested parent domain, it is missed. Hence, when trying to map pages to the nested parent, NULL dereference occurred. Also, there is potential memleak since there is no lock around domain->qi_batch allocation. To solve it, add a helper for qi_batch allocation, and call it in both the __cache_tag_assign_domain() and __cache_tag_assign_parent_domain(). BUG: kernel NULL pointer dereference, address: 0000000000000200 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 8104795067 P4D 0 Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 223 UID: 0 PID: 4357 Comm: qemu-system-x86 Not tainted 6.13.0-rc1-00028-g4b50c3c3b998-dirty #2632 Call Trace: ? __die+0x24/0x70 ? page_fault_oops+0x80/0x150 ? do_user_addr_fault+0x63/0x7b0 ? exc_page_fault+0x7c/0x220 ? asm_exc_page_fault+0x26/0x30 ? cache_tag_flush_range_np+0x13c/0x260 intel_iommu_iotlb_sync_map+0x1a/0x30 iommu_map+0x61/0xf0 batch_to_domain+0x188/0x250 iopt_area_fill_domains+0x125/0x320 ? rcu_is_watching+0x11/0x50 iopt_map_pages+0x63/0x100 iopt_map_common.isra.0+0xa7/0x190 iopt_map_user_pages+0x6a/0x80 iommufd_ioas_map+0xcd/0x1d0 iommufd_fops_ioctl+0x118/0x1c0 __x64_sys_ioctl+0x93/0xc0 do_syscall_64+0x71/0x140 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Frequently asked questions

What is CVE-2024-56668?
In the Linux kernel, the following vulnerability has been resolved: iommu/vt-d: Fix qi_batch NULL pointer with nested parent domain The qi_batch is allocated when assigning cache tag for a domain. While for nested parent domain, it is missed. Hence, when trying to map pages to the nested parent, NULL dereference occurred. Also, there is potential memleak since there is no lock around domain->qi_batch allocation. To solve it, add a helper for qi_batch allocation, and call it in both the __cache_tag_assign_domain() and __cache_tag_assign_parent_domain(). BUG: kernel NULL pointer dereference, address: 0000000000000200 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 8104795067 P4D 0 Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 223 UID: 0 PID: 4357 Comm: qemu-system-x86 Not tainted 6.13.0-rc1-00028-g4b50c3c3b998-dirty #2632 Call Trace: ? __die+0x24/0x70 ? page_fault_oops+0x80/0x150 ? do_user_addr_fault+0x63/0x7b0 ? exc_page_fault+0x7c/0x220 ? asm_exc_page_fault+0x26/0x30 ? cache_tag_flush_range_np+0x13c/0x260 intel_iommu_iotlb_sync_map+0x1a/0x30 iommu_map+0x61/0xf0 batch_to_domain+0x188/0x250 iopt_area_fill_domains+0x125/0x320 ? rcu_is_watching+0x11/0x50 iopt_map_pages+0x63/0x100 iopt_map_common.isra.0+0xa7/0x190 iopt_map_user_pages+0x6a/0x80 iommufd_ioas_map+0xcd/0x1d0 iommufd_fops_ioctl+0x118/0x1c0 __x64_sys_ioctl+0x93/0xc0 do_syscall_64+0x71/0x140 entry_SYSCALL_64_after_hwframe+0x76/0x7e
How severe is CVE-2024-56668?
CVE-2024-56668 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2024-56668 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (8th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-56668?
CVE-2024-56668 primarily affects Linux Linux Kernel. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2024-56668?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2024-56668 have an EU (EUVD) identifier?
Yes. CVE-2024-56668 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-53316.
When was CVE-2024-56668 published?
CVE-2024-56668 was published on 2024-12-27 and last updated on 2026-06-17.

References

Affected products (3)

More vulnerabilities in Linux Linux Kernel

All CVEs affecting Linux Linux Kernel →

Other CWE-401 (Missing Release of Memory after Effective Lifetime) vulnerabilities

Browse all CWE-401 (Missing Release of Memory after Effective Lifetime) vulnerabilities →