CVE-2021-47100

MEDIUM
Published Mar 4, 2024 Modified Feb 3, 2025 CWE-416

Description

In the Linux kernel, the following vulnerability has been resolved: ipmi: Fix UAF when uninstall ipmi_si and ipmi_msghandler module Hi, When testing install and uninstall of ipmi_si.ko and ipmi_msghandler.ko, the system crashed. The log as follows: [ 141.087026] BUG: unable to handle kernel paging request at ffffffffc09b3a5a [ 141.087241] PGD 8fe4c0d067 P4D 8fe4c0d067 PUD 8fe4c0f067 PMD 103ad89067 PTE 0 [ 141.087464] Oops: 0010 [#1] SMP NOPTI [ 141.087580] CPU: 67 PID: 668 Comm: kworker/67:1 Kdump: loaded Not tainted 4.18.0.x86_64 #47 [ 141.088009] Workqueue: events 0xffffffffc09b3a40 [ 141.088009] RIP: 0010:0xffffffffc09b3a5a [ 141.088009] Code: Bad RIP value. [ 141.088009] RSP: 0018:ffffb9094e2c3e88 EFLAGS: 00010246 [ 141.088009] RAX: 0000000000000000 RBX: ffff9abfdb1f04a0 RCX: 0000000000000000 [ 141.088009] RDX: 0000000000000000 RSI: 0000000000000246 RDI: 0000000000000246 [ 141.088009] RBP: 0000000000000000 R08: ffff9abfffee3cb8 R09: 00000000000002e1 [ 141.088009] R10: ffffb9094cb73d90 R11: 00000000000f4240 R12: ffff9abfffee8700 [ 141.088009] R13: 0000000000000000 R14: ffff9abfdb1f04a0 R15: ffff9abfdb1f04a8 [ 141.088009] FS: 0000000000000000(0000) GS:ffff9abfffec0000(0000) knlGS:0000000000000000 [ 141.088009] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 141.088009] CR2: ffffffffc09b3a30 CR3: 0000008fe4c0a001 CR4: 00000000007606e0 [ 141.088009] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 141.088009] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 141.088009] PKRU: 55555554 [ 141.088009] Call Trace: [ 141.088009] ? process_one_work+0x195/0x390 [ 141.088009] ? worker_thread+0x30/0x390 [ 141.088009] ? process_one_work+0x390/0x390 [ 141.088009] ? kthread+0x10d/0x130 [ 141.088009] ? kthread_flush_work_fn+0x10/0x10 [ 141.088009] ? ret_from_fork+0x35/0x40] BUG: unable to handle kernel paging request at ffffffffc0b28a5a [ 200.223240] PGD 97fe00d067 P4D 97fe00d067 PUD 97fe00f067 PMD a580cbf067 PTE 0 [ 200.223464] Oops: 0010 [#1] SMP NOPTI [ 200.223579] CPU: 63 PID: 664 Comm: kworker/63:1 Kdump: loaded Not tainted 4.18.0.x86_64 #46 [ 200.224008] Workqueue: events 0xffffffffc0b28a40 [ 200.224008] RIP: 0010:0xffffffffc0b28a5a [ 200.224008] Code: Bad RIP value. [ 200.224008] RSP: 0018:ffffbf3c8e2a3e88 EFLAGS: 00010246 [ 200.224008] RAX: 0000000000000000 RBX: ffffa0799ad6bca0 RCX: 0000000000000000 [ 200.224008] RDX: 0000000000000000 RSI: 0000000000000246 RDI: 0000000000000246 [ 200.224008] RBP: 0000000000000000 R08: ffff9fe43fde3cb8 R09: 00000000000000d5 [ 200.224008] R10: ffffbf3c8cb53d90 R11: 00000000000f4240 R12: ffff9fe43fde8700 [ 200.224008] R13: 0000000000000000 R14: ffffa0799ad6bca0 R15: ffffa0799ad6bca8 [ 200.224008] FS: 0000000000000000(0000) GS:ffff9fe43fdc0000(0000) knlGS:0000000000000000 [ 200.224008] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 200.224008] CR2: ffffffffc0b28a30 CR3: 00000097fe00a002 CR4: 00000000007606e0 [ 200.224008] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 200.224008] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 200.224008] PKRU: 55555554 [ 200.224008] Call Trace: [ 200.224008] ? process_one_work+0x195/0x390 [ 200.224008] ? worker_thread+0x30/0x390 [ 200.224008] ? process_one_work+0x390/0x390 [ 200.224008] ? kthread+0x10d/0x130 [ 200.224008] ? kthread_flush_work_fn+0x10/0x10 [ 200.224008] ? ret_from_fork+0x35/0x40 [ 200.224008] kernel fault(0x1) notification starting on CPU 63 [ 200.224008] kernel fault(0x1) notification finished on CPU 63 [ 200.224008] CR2: ffffffffc0b28a5a [ 200.224008] ---[ end trace c82a412d93f57412 ]--- The reason is as follows: T1: rmmod ipmi_si. ->ipmi_unregister_smi() -> ipmi_bmc_unregister() -> __ipmi_bmc_unregister() -> kref_put(&bmc->usecount, cleanup_bmc_device); -> schedule_work(&bmc->remove_work); T2: rmmod ipmi_msghandl ---truncated---

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CVSS v3.1 Score

5.5
MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-416 Use After Free

Affected Products

Vendor Product
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel

References

Frequently Asked Questions

What is CVE-2021-47100? +
In the Linux kernel, the following vulnerability has been resolved: ipmi: Fix UAF when uninstall ipmi_si and ipmi_msghandler module Hi, When testing install and uninstall of ipmi_si.ko and ipmi_msghandler.ko, the system crashed. The log as follows: [ 141.087026] BUG: unable to handle kernel paging request at ffffffffc09b3a5a [ 141.087241] PGD 8fe4c0d067 P4D 8fe4c0d067 PUD 8fe4c0f067 PMD 103ad89067 PTE 0 [ 141.087464] Oops: 0010 [#1] SMP NOPTI [ 141.087580] CPU: 67 PID: 668 Comm: kworker/67:1 Kdump: loaded Not tainted 4.18.0.x86_64 #47 [ 141.088009] Workqueue: events 0xffffffffc09b3a40 [ 141.088009] RIP: 0010:0xffffffffc09b3a5a [ 141.088009] Code: Bad RIP value. [ 141.088009] RSP: 0018:ffffb9094e2c3e88 EFLAGS: 00010246 [ 141.088009] RAX: 0000000000000000 RBX: ffff9abfdb1f04a0 RCX: 0000000000000000 [ 141.088009] RDX: 0000000000000000 RSI: 0000000000000246 RDI: 0000000000000246 [ 141.088009] RBP: 0000000000000000 R08: ffff9abfffee3cb8 R09: 00000000000002e1 [ 141.088009] R10: ffffb9094cb73d90 R11: 00000000000f4240 R12: ffff9abfffee8700 [ 141.088009] R13: 0000000000000000 R14: ffff9abfdb1f04a0 R15: ffff9abfdb1f04a8 [ 141.088009] FS: 0000000000000000(0000) GS:ffff9abfffec0000(0000) knlGS:0000000000000000 [ 141.088009] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 141.088009] CR2: ffffffffc09b3a30 CR3: 0000008fe4c0a001 CR4: 00000000007606e0 [ 141.088009] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 141.088009] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 141.088009] PKRU: 55555554 [ 141.088009] Call Trace: [ 141.088009] ? process_one_work+0x195/0x390 [ 141.088009] ? worker_thread+0x30/0x390 [ 141.088009] ? process_one_work+0x390/0x390 [ 141.088009] ? kthread+0x10d/0x130 [ 141.088009] ? kthread_flush_work_fn+0x10/0x10 [ 141.088009] ? ret_from_fork+0x35/0x40] BUG: unable to handle kernel paging request at ffffffffc0b28a5a [ 200.223240] PGD 97fe00d067 P4D 97fe00d067 PUD 97fe00f067 PMD a580cbf067 PTE 0 [ 200.223464] Oops: 0010 [#1] SMP NOPTI [ 200.223579] CPU: 63 PID: 664 Comm: kworker/63:1 Kdump: loaded Not tainted 4.18.0.x86_64 #46 [ 200.224008] Workqueue: events 0xffffffffc0b28a40 [ 200.224008] RIP: 0010:0xffffffffc0b28a5a [ 200.224008] Code: Bad RIP value. [ 200.224008] RSP: 0018:ffffbf3c8e2a3e88 EFLAGS: 00010246 [ 200.224008] RAX: 0000000000000000 RBX: ffffa0799ad6bca0 RCX: 0000000000000000 [ 200.224008] RDX: 0000000000000000 RSI: 0000000000000246 RDI: 0000000000000246 [ 200.224008] RBP: 0000000000000000 R08: ffff9fe43fde3cb8 R09: 00000000000000d5 [ 200.224008] R10: ffffbf3c8cb53d90 R11: 00000000000f4240 R12: ffff9fe43fde8700 [ 200.224008] R13: 0000000000000000 R14: ffffa0799ad6bca0 R15: ffffa0799ad6bca8 [ 200.224008] FS: 0000000000000000(0000) GS:ffff9fe43fdc0000(0000) knlGS:0000000000000000 [ 200.224008] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 200.224008] CR2: ffffffffc0b28a30 CR3: 00000097fe00a002 CR4: 00000000007606e0 [ 200.224008] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 200.224008] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 200.224008] PKRU: 55555554 [ 200.224008] Call Trace: [ 200.224008] ? process_one_work+0x195/0x390 [ 200.224008] ? worker_thread+0x30/0x390 [ 200.224008] ? process_one_work+0x390/0x390 [ 200.224008] ? kthread+0x10d/0x130 [ 200.224008] ? kthread_flush_work_fn+0x10/0x10 [ 200.224008] ? ret_from_fork+0x35/0x40 [ 200.224008] kernel fault(0x1) notification starting on CPU 63 [ 200.224008] kernel fault(0x1) notification finished on CPU 63 [ 200.224008] CR2: ffffffffc0b28a5a [ 200.224008] ---[ end trace c82a412d93f57412 ]--- The reason is as follows: T1: rmmod ipmi_si. ->ipmi_unregister_smi() -> ipmi_bmc_unregister() -> __ipmi_bmc_unregister() -> kref_put(&bmc->usecount, cleanup_bmc_device); -> schedule_work(&bmc->remove_work); T2: rmmod ipmi_msghandl ---truncated--- It has a CVSS v3.1 base score of 5.5 (MEDIUM).
How severe is CVE-2021-47100? +
CVE-2021-47100 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.
What products are affected by CVE-2021-47100? +
CVE-2021-47100 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2021-47100? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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