# CVE-2026-46289: lib/scatterlist: fix length calculations in extract_kvec_to_sg

> A flaw in Linux kernel scatterlist extraction allows memory corruption via incorrect length calculations, potentially leading to denial of service or information disclosure.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 8 Jun 2026
- **Updated:** 5 Aug 2026
- **Also known as:** AZL-89592, BELL-CVE-2026-46289, DEBIAN-CVE-2026-46289, GHSA-qp34-4r23-mcwx, ROOT-OS-UBUNTU-2404-CVE-2026-46289, UBUNTU-CVE-2026-46289

## What is CVE-2026-46289?

CVE-2026-46289 is a critical memory corruption vulnerability in Linux kernel, published on 8 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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

lib/scatterlist: fix length calculations in extract_kvec_to_sg

Patch series "Fix bugs in extract_iter_to_sg()", v3.

Fix bugs in the kvec and user variants of extract_iter_to_sg.  This series
is growing due to useful remarks made by sashiko.dev.

The main bugs are:
- The length for an sglist entry when extracting from
  a kvec can exceed the number of bytes in the page. This
  is obviously not intended.
- When extracting a user buffer the sglist is temporarily
  used as a scratch buffer for extracted page pointers.
  If the sglist already contains some elements this scratch
  buffer could overlap with existing entries in the sglist.

The series adds test cases to the kunit_iov_iter test that demonstrate all
of these bugs.  Additionally, there is a memory leak fix for the test
itself.

The bugs were orignally introduced into kernel v6.3 where the function
lived in fs/netfs/iterator.c.  It was later moved to lib/scatterlist.c in
v6.5.  Thus the actual fix is only marked for backports to v6.5+.

This patch (of 5):

When extracting from a kvec to a scatterlist, do not cross page
boundaries.  The required length was already calculated but not used as
intended.

Adjust the copied length if the loop runs out of sglist entries without
extracting everything.

While there, return immediately from extract_iter_to_sg if there are no
sglist entries at all.

A subsequent commit will add kunit test cases that demonstrate that the
patch is necessary.

Weakness: CWE-401 (Missing Release of Memory after Effective Lifetime)

## Which versions are affected by CVE-2026-46289?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-46289?

Apply the vendor's patch.

## Is CVE-2026-46289 being exploited?

There is no known exploitation of CVE-2026-46289 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-2026-46289 and fix it if it is affected.

What it is: CVE-2026-46289 is a critical memory corruption vulnerability in Linux kernel, published on 8 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-46289 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-2026-46289/ (Markdown: https://insights.sbomify.com/CVE-2026-46289/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-46289
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-46289
- OSV: https://osv.dev/vulnerability/CVE-2026-46289

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-46289/
Summaries are generated and may contain mistakes; the official description above is the record.