CVE-2024-26746

CVE-2024-26746 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.

Key facts

Description

In the Linux kernel, the following vulnerability has been resolved: dmaengine: idxd: Ensure safe user copy of completion record If CONFIG_HARDENED_USERCOPY is enabled, copying completion record from event log cache to user triggers a kernel bug. [ 1987.159822] usercopy: Kernel memory exposure attempt detected from SLUB object 'dsa0' (offset 74, size 31)! [ 1987.170845] ------------[ cut here ]------------ [ 1987.176086] kernel BUG at mm/usercopy.c:102! [ 1987.180946] invalid opcode: 0000 [#1] PREEMPT SMP NOPTI [ 1987.186866] CPU: 17 PID: 528 Comm: kworker/17:1 Not tainted 6.8.0-rc2+ #5 [ 1987.194537] Hardware name: Intel Corporation AvenueCity/AvenueCity, BIOS BHSDCRB1.86B.2492.D03.2307181620 07/18/2023 [ 1987.206405] Workqueue: wq0.0 idxd_evl_fault_work [idxd] [ 1987.212338] RIP: 0010:usercopy_abort+0x72/0x90 [ 1987.217381] Code: 58 65 9c 50 48 c7 c2 17 85 61 9c 57 48 c7 c7 98 fd 6b 9c 48 0f 44 d6 48 c7 c6 b3 08 62 9c 4c 89 d1 49 0f 44 f3 e8 1e 2e d5 ff <0f> 0b 49 c7 c1 9e 42 61 9c 4c 89 cf 4d 89 c8 eb a9 66 66 2e 0f 1f [ 1987.238505] RSP: 0018:ff62f5cf20607d60 EFLAGS: 00010246 [ 1987.244423] RAX: 000000000000005f RBX: 000000000000001f RCX: 0000000000000000 [ 1987.252480] RDX: 0000000000000000 RSI: ffffffff9c61429e RDI: 00000000ffffffff [ 1987.260538] RBP: ff62f5cf20607d78 R08: ff2a6a89ef3fffe8 R09: 00000000fffeffff [ 1987.268595] R10: ff2a6a89eed00000 R11: 0000000000000003 R12: ff2a66934849c89a [ 1987.276652] R13: 0000000000000001 R14: ff2a66934849c8b9 R15: ff2a66934849c899 [ 1987.284710] FS: 0000000000000000(0000) GS:ff2a66b22fe40000(0000) knlGS:0000000000000000 [ 1987.293850] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1987.300355] CR2: 00007fe291a37000 CR3: 000000010fbd4005 CR4: 0000000000f71ef0 [ 1987.308413] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1987.316470] DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400 [ 1987.324527] PKRU: 55555554 [ 1987.327622] Call Trace: [ 1987.330424] <TASK> [ 1987.332826] ? show_regs+0x6e/0x80 [ 1987.336703] ? die+0x3c/0xa0 [ 1987.339988] ? do_trap+0xd4/0xf0 [ 1987.343662] ? do_error_trap+0x75/0xa0 [ 1987.347922] ? usercopy_abort+0x72/0x90 [ 1987.352277] ? exc_invalid_op+0x57/0x80 [ 1987.356634] ? usercopy_abort+0x72/0x90 [ 1987.360988] ? asm_exc_invalid_op+0x1f/0x30 [ 1987.365734] ? usercopy_abort+0x72/0x90 [ 1987.370088] __check_heap_object+0xb7/0xd0 [ 1987.374739] __check_object_size+0x175/0x2d0 [ 1987.379588] idxd_copy_cr+0xa9/0x130 [idxd] [ 1987.384341] idxd_evl_fault_work+0x127/0x390 [idxd] [ 1987.389878] process_one_work+0x13e/0x300 [ 1987.394435] ? __pfx_worker_thread+0x10/0x10 [ 1987.399284] worker_thread+0x2f7/0x420 [ 1987.403544] ? _raw_spin_unlock_irqrestore+0x2b/0x50 [ 1987.409171] ? __pfx_worker_thread+0x10/0x10 [ 1987.414019] kthread+0x107/0x140 [ 1987.417693] ? __pfx_kthread+0x10/0x10 [ 1987.421954] ret_from_fork+0x3d/0x60 [ 1987.426019] ? __pfx_kthread+0x10/0x10 [ 1987.430281] ret_from_fork_asm+0x1b/0x30 [ 1987.434744] </TASK> The issue arises because event log cache is created using kmem_cache_create() which is not suitable for user copy. Fix the issue by creating event log cache with kmem_cache_create_usercopy(), ensuring safe user copy.

Frequently asked questions

What is CVE-2024-26746?
In the Linux kernel, the following vulnerability has been resolved: dmaengine: idxd: Ensure safe user copy of completion record If CONFIG_HARDENED_USERCOPY is enabled, copying completion record from event log cache to user triggers a kernel bug. [ 1987.159822] usercopy: Kernel memory exposure attempt detected from SLUB object 'dsa0' (offset 74, size 31)! [ 1987.170845] ------------[ cut here ]------------ [ 1987.176086] kernel BUG at mm/usercopy.c:102! [ 1987.180946] invalid opcode: 0000 [#1] PREEMPT SMP NOPTI [ 1987.186866] CPU: 17 PID: 528 Comm: kworker/17:1 Not tainted 6.8.0-rc2+ #5 [ 1987.194537] Hardware name: Intel Corporation AvenueCity/AvenueCity, BIOS BHSDCRB1.86B.2492.D03.2307181620 07/18/2023 [ 1987.206405] Workqueue: wq0.0 idxd_evl_fault_work [idxd] [ 1987.212338] RIP: 0010:usercopy_abort+0x72/0x90 [ 1987.217381] Code: 58 65 9c 50 48 c7 c2 17 85 61 9c 57 48 c7 c7 98 fd 6b 9c 48 0f 44 d6 48 c7 c6 b3 08 62 9c 4c 89 d1 49 0f 44 f3 e8 1e 2e d5 ff <0f> 0b 49 c7 c1 9e 42 61 9c 4c 89 cf 4d 89 c8 eb a9 66 66 2e 0f 1f [ 1987.238505] RSP: 0018:ff62f5cf20607d60 EFLAGS: 00010246 [ 1987.244423] RAX: 000000000000005f RBX: 000000000000001f RCX: 0000000000000000 [ 1987.252480] RDX: 0000000000000000 RSI: ffffffff9c61429e RDI: 00000000ffffffff [ 1987.260538] RBP: ff62f5cf20607d78 R08: ff2a6a89ef3fffe8 R09: 00000000fffeffff [ 1987.268595] R10: ff2a6a89eed00000 R11: 0000000000000003 R12: ff2a66934849c89a [ 1987.276652] R13: 0000000000000001 R14: ff2a66934849c8b9 R15: ff2a66934849c899 [ 1987.284710] FS: 0000000000000000(0000) GS:ff2a66b22fe40000(0000) knlGS:0000000000000000 [ 1987.293850] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1987.300355] CR2: 00007fe291a37000 CR3: 000000010fbd4005 CR4: 0000000000f71ef0 [ 1987.308413] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1987.316470] DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400 [ 1987.324527] PKRU: 55555554 [ 1987.327622] Call Trace: [ 1987.330424] <TASK> [ 1987.332826] ? show_regs+0x6e/0x80 [ 1987.336703] ? die+0x3c/0xa0 [ 1987.339988] ? do_trap+0xd4/0xf0 [ 1987.343662] ? do_error_trap+0x75/0xa0 [ 1987.347922] ? usercopy_abort+0x72/0x90 [ 1987.352277] ? exc_invalid_op+0x57/0x80 [ 1987.356634] ? usercopy_abort+0x72/0x90 [ 1987.360988] ? asm_exc_invalid_op+0x1f/0x30 [ 1987.365734] ? usercopy_abort+0x72/0x90 [ 1987.370088] __check_heap_object+0xb7/0xd0 [ 1987.374739] __check_object_size+0x175/0x2d0 [ 1987.379588] idxd_copy_cr+0xa9/0x130 [idxd] [ 1987.384341] idxd_evl_fault_work+0x127/0x390 [idxd] [ 1987.389878] process_one_work+0x13e/0x300 [ 1987.394435] ? __pfx_worker_thread+0x10/0x10 [ 1987.399284] worker_thread+0x2f7/0x420 [ 1987.403544] ? _raw_spin_unlock_irqrestore+0x2b/0x50 [ 1987.409171] ? __pfx_worker_thread+0x10/0x10 [ 1987.414019] kthread+0x107/0x140 [ 1987.417693] ? __pfx_kthread+0x10/0x10 [ 1987.421954] ret_from_fork+0x3d/0x60 [ 1987.426019] ? __pfx_kthread+0x10/0x10 [ 1987.430281] ret_from_fork_asm+0x1b/0x30 [ 1987.434744] </TASK> The issue arises because event log cache is created using kmem_cache_create() which is not suitable for user copy. Fix the issue by creating event log cache with kmem_cache_create_usercopy(), ensuring safe user copy.
How severe is CVE-2024-26746?
CVE-2024-26746 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-2024-26746 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-26746?
CVE-2024-26746 primarily affects Linux Linux Kernel. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2024-26746?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2024-26746 have an EU (EUVD) identifier?
Yes. CVE-2024-26746 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-24008.
When was CVE-2024-26746 published?
CVE-2024-26746 was published on 2024-04-04 and last updated on 2026-06-17.

References

Affected products (7)

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