# CVE-2026-31675: net/sched: sch_netem: fix out-of-bounds access in packet corruption

> A local attacker can trigger an out-of-bounds memory access in the Linux kernel's netem scheduler by sending specific non-linear packets, potentially leading to code execution or system crash.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:** 25 Apr 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-84204, BELL-CVE-2026-31675, DEBIAN-CVE-2026-31675, GHSA-2gh3-wm75-4q8m, ROOT-OS-DEBIAN-11-CVE-2026-31675, ROOT-OS-DEBIAN-12-CVE-2026-31675, ROOT-OS-UBUNTU-2204-CVE-2026-31675, ROOT-OS-UBUNTU-2404-CVE-2026-31675, UBUNTU-CVE-2026-31675

## What is CVE-2026-31675?

CVE-2026-31675 is a high-severity memory corruption vulnerability in Linux kernel, published on 25 Apr 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:

net/sched: sch_netem: fix out-of-bounds access in packet corruption

In netem_enqueue(), the packet corruption logic uses
get_random_u32_below(skb_headlen(skb)) to select an index for
modifying skb->data. When an AF_PACKET TX_RING sends fully non-linear
packets over an IPIP tunnel, skb_headlen(skb) evaluates to 0.

Passing 0 to get_random_u32_below() takes the variable-ceil slow path
which returns an unconstrained 32-bit random integer. Using this
unconstrained value as an offset into skb->data results in an
out-of-bounds memory access.

Fix this by verifying skb_headlen(skb) is non-zero before attempting
to corrupt the linear data area. Fully non-linear packets will silently
bypass the corruption logic.

Weakness: CWE-125 (Out-of-bounds Read), CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2026-31675?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-31675?

Apply the vendor's patch.

## Is CVE-2026-31675 being exploited?

There is no known exploitation of CVE-2026-31675 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-2026-31675 and fix it if it is affected.

What it is: CVE-2026-31675 is a high-severity memory corruption vulnerability in Linux kernel, published on 25 Apr 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-2026-31675 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-2026-31675/ (Markdown: https://insights.sbomify.com/CVE-2026-31675/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31675
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31675
- OSV: https://osv.dev/vulnerability/CVE-2026-31675

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31675/
Summaries are generated and may contain mistakes; the official description above is the record.