# CVE-2021-47475: linux: In the Linux kernel, the following vulnerability has been resolved:  comedi: vmk80xx: fix transfer-buffer overflows...

CVE-2021-47475 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-47475, released May 22, 2024. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2021-47475
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0026
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 22, 2024

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 5.15.3-1 | [DEBIAN-CVE-2021-47475](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47475.md) | May 22, 2024 |
| Linux | linux Debian 13.5 (trixie) | 5.15.3-1 | [DEBIAN-CVE-2021-47475](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47475.md) | May 22, 2024 |
| Linux | linux Debian 14 | 5.15.3-1 | [DEBIAN-CVE-2021-47475](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47475.md) | May 22, 2024 |

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