Linux Kernel up to 5.15.6 sata_fsl sata_fsl.ko use after free

Summaryinfo

A vulnerability identified as critical has been detected in Linux Kernel up to 5.15.6. The impacted element is an unknown function in the library sata_fsl.ko of the component sata_fsl. Performing a manipulation results in use after free. This vulnerability was named CVE-2021-47549. There is no available exploit. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 5.15.6. It has been classified as critical. This affects some unknown functionality in the library sata_fsl.ko of the component sata_fsl. The manipulation with an unknown input leads to a use after free vulnerability. CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: sata_fsl: fix UAF in sata_fsl_port_stop when rmmod sata_fsl When the `rmmod sata_fsl.ko` command is executed in the PPC64 GNU/Linux, a bug is reported: ================================================================== BUG: Unable to handle kernel data access on read at 0x80000800805b502c Oops: Kernel access of bad area, sig: 11 [#1] NIP [c0000000000388a4] .ioread32+0x4/0x20 LR [80000000000c6034] .sata_fsl_port_stop+0x44/0xe0 [sata_fsl] Call Trace: .free_irq+0x1c/0x4e0 (unreliable) .ata_host_stop+0x74/0xd0 [libata] .release_nodes+0x330/0x3f0 .device_release_driver_internal+0x178/0x2c0 .driver_detach+0x64/0xd0 .bus_remove_driver+0x70/0xf0 .driver_unregister+0x38/0x80 .platform_driver_unregister+0x14/0x30 .fsl_sata_driver_exit+0x18/0xa20 [sata_fsl] .__se_sys_delete_module+0x1ec/0x2d0 .system_call_exception+0xfc/0x1f0 system_call_common+0xf8/0x200 ================================================================== The triggering of the BUG is shown in the following stack: driver_detach device_release_driver_internal __device_release_driver drv->remove(dev) --> platform_drv_remove/platform_remove drv->remove(dev) --> sata_fsl_remove iounmap(host_priv->hcr_base); <---- unmap kfree(host_priv); <---- free devres_release_all release_nodes dr->node.release(dev, dr->data) --> ata_host_stop ap->ops->port_stop(ap) --> sata_fsl_port_stop ioread32(hcr_base + HCONTROL) <---- UAF host->ops->host_stop(host) The iounmap(host_priv->hcr_base) and kfree(host_priv) functions should not be executed in drv->remove. These functions should be executed in host_stop after port_stop. Therefore, we move these functions to the new function sata_fsl_host_stop and bind the new function to host_stop.

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2021-47549. The exploitability is told to be easy. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 08/09/2025).

The vulnerability scanner Nessus provides a plugin with the ID 246379 (Linux Distros Unpatched Vulnerability : CVE-2021-47549), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 4.4.294, 4.9.292, 4.14.257, 4.19.220, 5.4.164, 5.10.84 or 5.15.7 eliminates this vulnerability. Applying the patch cdcd80292106/91ba94d3f7af/325ea49fc43c/0769449b0a5e/77393806c76b/4a46b2f5dce0/adf098e2a8a1/6c8ad7e8cf29 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (246379). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 4.4.293
• 4.9.291
• 4.14.256
• 4.19.219
• 5.4.163
• 5.10.0
• 5.10.1
• 5.10.2
• 5.10.3
• 5.10.4
• 5.10.5
• 5.10.6
• 5.10.7
• 5.10.8
• 5.10.9
• 5.10.10
• 5.10.11
• 5.10.12
• 5.10.13
• 5.10.14
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• 5.10.20
• 5.10.21
• 5.10.22
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• 5.10.25
• 5.10.26
• 5.10.27
• 5.10.28
• 5.10.29
• 5.10.30
• 5.10.31
• 5.10.32
• 5.10.33
• 5.10.34
• 5.10.35
• 5.10.36
• 5.10.37
• 5.10.38
• 5.10.39
• 5.10.40
• 5.10.41
• 5.10.42
• 5.10.43
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• 5.10.48
• 5.10.49
• 5.10.50
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• 5.10.53
• 5.10.54
• 5.10.55
• 5.10.56
• 5.10.57
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• 5.10.64
• 5.10.65
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• 5.10.67
• 5.10.68
• 5.10.69
• 5.10.70
• 5.10.71
• 5.10.72
• 5.10.73
• 5.10.74
• 5.10.75
• 5.10.76
• 5.10.77
• 5.10.78
• 5.10.79
• 5.10.80
• 5.10.81
• 5.10.82
• 5.10.83
• 5.15.0
• 5.15.1
• 5.15.2
• 5.15.3
• 5.15.4
• 5.15.5
• 5.15.6

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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Entryinfo

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