# CVE-2026-31675

> Vulnerability · severity: **HIGH** (CVSS 7.8).

## 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.

## Key facts

- **CVE ID:** CVE-2026-31675
- **Published:** 2026-04-25
- **CVSS severity:** HIGH
- **CVSS base score:** 7.8
- **CWE codes:** CWE-125

## Affected products

- `linux:linux_kernel`

## Primary sources

- NIST NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31675

## Citation

> AI Analytics. CVE-2026-31675. Retrieved 2026-07-29 from https://api.ai-analytics.org/cve/CVE-2026-31675. Derived from NIST NVD. Licensed CC0.

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