# CVE-2026-46101: netfilter: reject zero shift in nft_bitwise

> A zero shift operand in nft_bitwise causes undefined behavior, potentially leading to a denial of service in the Linux kernel.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/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:** 27 May 2026
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-88502, BELL-CVE-2026-46101, DEBIAN-CVE-2026-46101, GHSA-8x7w-42q6-mv4p, ROOT-OS-DEBIAN-11-CVE-2026-46101, ROOT-OS-DEBIAN-12-CVE-2026-46101, ROOT-OS-UBUNTU-2204-CVE-2026-46101, ROOT-OS-UBUNTU-2404-CVE-2026-46101, UBUNTU-CVE-2026-46101

## What is CVE-2026-46101?

CVE-2026-46101 is a medium-severity denial of service vulnerability in Linux kernel, published on 27 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:

netfilter: reject zero shift in nft_bitwise

Reject zero shift operands for nft_bitwise left and right shift
expressions during initialization.

The carry propagation logic computes the carry from the adjacent 32-bit
word using BITS_PER_TYPE(u32) - shift. A zero shift operand turns this
into a 32-bit shift, which is undefined behaviour.

Reject zero shift operands in the control plane, alongside the existing
check for values greater than or equal to 32, so malformed rules never
reach the packet path.

## Which versions are affected by CVE-2026-46101?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-46101?

Apply the vendor's patch.

## Is CVE-2026-46101 being exploited?

There is no known exploitation of CVE-2026-46101 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-2026-46101 and fix it if it is affected.

What it is: CVE-2026-46101 is a medium-severity denial of service vulnerability in Linux kernel, published on 27 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-2026-46101 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-2026-46101/ (Markdown: https://insights.sbomify.com/CVE-2026-46101/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-46101
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-46101
- OSV: https://osv.dev/vulnerability/CVE-2026-46101

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-46101/
Summaries are generated and may contain mistakes; the official description above is the record.