CVE-2021-47475

HIGH
Published May 22, 2024 Modified Sep 24, 2025 CWE-787

Description

In the Linux kernel, the following vulnerability has been resolved: comedi: vmk80xx: fix transfer-buffer overflows The driver uses endpoint-sized USB transfer buffers but up until recently had no sanity checks on the sizes. Commit e1f13c879a7c ("staging: comedi: check validity of wMaxPacketSize of usb endpoints found") inadvertently fixed NULL-pointer dereferences when accessing the transfer buffers in case a malicious device has a zero wMaxPacketSize. Make sure to allocate buffers large enough to handle also the other accesses that are done without a size check (e.g. byte 18 in vmk80xx_cnt_insn_read() for the VMK8061_MODEL) to avoid writing beyond the buffers, for example, when doing descriptor fuzzing. The original driver was for a low-speed device with 8-byte buffers. Support was later added for a device that uses bulk transfers and is presumably a full-speed device with a maximum 64-byte wMaxPacketSize.

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CVSS v3.1 Score

7.8
HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Weakness Type (CWE)

CWE-787 Out-of-bounds Write

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

References

Advisories & Patches

https://git.kernel.org/stable/c/06ac746d57e6d32b062e220415c607b7e2e0fa50 https://git.kernel.org/stable/c/199acd8c110e3ae62833c24f632b0bb1c9f012a9 https://git.kernel.org/stable/c/278484ae93297b1bb1ce755f9d3b6d95a48c7d47 https://git.kernel.org/stable/c/33d7a470730dfe7c9bfc8da84575cf2cedd60d00 https://git.kernel.org/stable/c/40d2a7e278e2e7c0a5fd7e997e7eb63945bf93f7 https://git.kernel.org/stable/c/5229159f1d052821007aff1a1beb7873eacf1a9f https://git.kernel.org/stable/c/7a2021b896de1ad559d33b5c5cdd20b982242088 https://git.kernel.org/stable/c/a23461c47482fc232ffc9b819539d1f837adf2b1 https://git.kernel.org/stable/c/ec85bcff4ed09260243d8f39faba99e1041718ba https://git.kernel.org/stable/c/06ac746d57e6d32b062e220415c607b7e2e0fa50 https://git.kernel.org/stable/c/199acd8c110e3ae62833c24f632b0bb1c9f012a9 https://git.kernel.org/stable/c/278484ae93297b1bb1ce755f9d3b6d95a48c7d47 https://git.kernel.org/stable/c/33d7a470730dfe7c9bfc8da84575cf2cedd60d00 https://git.kernel.org/stable/c/40d2a7e278e2e7c0a5fd7e997e7eb63945bf93f7 https://git.kernel.org/stable/c/5229159f1d052821007aff1a1beb7873eacf1a9f https://git.kernel.org/stable/c/7a2021b896de1ad559d33b5c5cdd20b982242088 https://git.kernel.org/stable/c/a23461c47482fc232ffc9b819539d1f837adf2b1 https://git.kernel.org/stable/c/ec85bcff4ed09260243d8f39faba99e1041718ba

Frequently Asked Questions

What is CVE-2021-47475? +
In the Linux kernel, the following vulnerability has been resolved: comedi: vmk80xx: fix transfer-buffer overflows The driver uses endpoint-sized USB transfer buffers but up until recently had no sanity checks on the sizes. Commit e1f13c879a7c ("staging: comedi: check validity of wMaxPacketSize of usb endpoints found") inadvertently fixed NULL-pointer dereferences when accessing the transfer buffers in case a malicious device has a zero wMaxPacketSize. Make sure to allocate buffers large enough to handle also the other accesses that are done without a size check (e.g. byte 18 in vmk80xx_cnt_insn_read() for the VMK8061_MODEL) to avoid writing beyond the buffers, for example, when doing descriptor fuzzing. The original driver was for a low-speed device with 8-byte buffers. Support was later added for a device that uses bulk transfers and is presumably a full-speed device with a maximum 64-byte wMaxPacketSize. It has a CVSS v3.1 base score of 7.8 (HIGH).
How severe is CVE-2021-47475? +
CVE-2021-47475 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.
What products are affected by CVE-2021-47475? +
CVE-2021-47475 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-2021-47475? +
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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