# CVE-2026-43006: io_uring/rsrc: reject zero-length fixed buffer import

> A local attacker can trigger an out-of-bounds read in the Linux kernel's io_uring subsystem, potentially leaking memory or causing a crash.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 1 May 2026
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2026-43006, DEBIAN-CVE-2026-43006, GHSA-5mwr-6pqp-c5qm, UBUNTU-CVE-2026-43006

## What is CVE-2026-43006?

CVE-2026-43006 is a high-severity memory corruption vulnerability in Linux kernel, published on 1 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

io_uring/rsrc: reject zero-length fixed buffer import

validate_fixed_range() admits buf_addr at the exact end of the
registered region when len is zero, because the check uses strict
greater-than (buf_end > imu->ubuf + imu->len).  io_import_fixed()
then computes offset == imu->len, which causes the bvec skip logic
to advance past the last bio_vec entry and read bv_offset from
out-of-bounds slab memory.

Return early from io_import_fixed() when len is zero.  A zero-length
import has no data to transfer and should not walk the bvec array
at all.

  BUG: KASAN: slab-out-of-bounds in io_import_reg_buf+0x697/0x7f0
  Read of size 4 at addr ffff888002bcc254 by task poc/103
  Call Trace:
   io_import_reg_buf+0x697/0x7f0
   io_write_fixed+0xd9/0x250
   __io_issue_sqe+0xad/0x710
   io_issue_sqe+0x7d/0x1100
   io_submit_sqes+0x86a/0x23c0
   __do_sys_io_uring_enter+0xa98/0x1590
  Allocated by task 103:
  The buggy address is located 12 bytes to the right of
   allocated 584-byte region [ffff888002bcc000, ffff888002bcc248)

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-43006?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-43006?

Apply the vendor's patch.

## Is CVE-2026-43006 being exploited?

There is no known exploitation of CVE-2026-43006 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-43006 and fix it if it is affected.

What it is: CVE-2026-43006 is a high-severity memory corruption vulnerability in Linux kernel, published on 1 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-43006 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-43006/ (Markdown: https://insights.sbomify.com/CVE-2026-43006/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43006
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43006
- OSV: https://osv.dev/vulnerability/CVE-2026-43006

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43006/
Summaries are generated and may contain mistakes; the official description above is the record.