---
id: "CVE-2026-40694"
page: "https://infrastack.ai/live/CVE-2026-40694"
kind: "vulnerability"
aliases: ["CVE-2026-40694"]
title: "Hyperscan: out-of-bounds write lets a local user crash applications"
severity: "medium"
cvss: 5.8
epss: null
exploited: false
status: "open"
category: "package"
products: [{"name": "Hyperscan", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["hyperscan", "local-users", "multi-tenant", "package"]
not_affected_if: ["hyperscan-v5.4.2.1-or-later", "no-untrusted-local-users"]
published_at: "2026-11-10T18:17:38+00:00"
first_seen_at: "2026-11-10T18:22:57+00:00"
updated_at: "2026-11-10T18:25:04+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-40694", "first_seen_at": "2026-11-10T18:22:57+00:00"}]
exploit_sources: []
---

# Hyperscan: out-of-bounds write lets a local user crash applications

Link for people: https://infrastack.ai/live/CVE-2026-40694 (this .md is for agents)

Hyperscan, Intel's regular expression matching library, has an out-of-bounds write in versions before v5.4.2.1 that can be triggered from user-level code. An attacker with an authenticated local account can cause a denial of service by crashing the application that uses it.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Hyperscan affected range not listed fixed no fixed version listed

## How to check

- Check the Hyperscan version your application links against, for example with `pkg-config --modversion libhs` or the version pinned in your build files.
- Identify whether any local, unprivileged users can submit input to processes that use Hyperscan.

## Fix

- Hyperscan: move to `v5.4.2.1` or later

## Timeline

- 2026-11-10T18:22:57+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-40694

## From the sources

Out-of-bounds write for some Hyperscan before version v5.4.2.1 within Ring 3: User Applications may allow a denial of service. Unprivileged software adversary with an authenticated user combined with a low complexity attack may enable denial of service. This result may potentially occur via local access when attack requirements are present without special internal knowledge and requires no user interaction. The potential vulnerability may impact the confidentiality (low), integrity (low) and availability (high) of the vulnerable system, resulting in subsequent system confidentiality (none), integrity (none) and availability (none) impacts.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_