# CVE-2026-40694: Intel Hyperscan out-of-bounds write denial of service

Source: https://junglewise.ai/threats/cve-2026-40694-out-of-bounds-write-for-some-hyperscan-before-version-v5-4-2-1  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-10. Updated: 2026-11-10  
License: CC BY 4.0 with a link back

CVE-2026-40694 · Severity: info · Published 2026-11-10

Hyperscan is an Intel pattern matching library used in applications for regex and string matching. An out-of-bounds write vulnerability in Hyperscan before version 5.4.2.1 allows an unprivileged local attacker to cause a denial of service by crashing the application. The vulnerability requires local access and an authenticated user on the system.

Technologies: [Intel Hyperscan](https://junglewise.ai/threats/technologies/hyperscan). Vendors: [Intel](https://junglewise.ai/threats/vendors/intel).

## Quick answers

**Is CVE-2026-40694 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-40694 being exploited in the wild.

**How severe is CVE-2026-40694?** Informational severity, published 10 November 2026.

**Which products and versions are affected?** Intel Hyperscan before v5.4.2.1.

**Is there a fix for CVE-2026-40694?** Yes: fixed in Hyperscan v5.4.2.1. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-40694 attacked?** It is attacked with local access, in a software library.

**Am I affected by CVE-2026-40694?** Check whether you run Intel Hyperscan at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in Hyperscan v5.4.2.1

## Technical details

An out-of-bounds write in Hyperscan's Ring 3 user application handling allows a local, authenticated attacker with low attack complexity to trigger denial of service. The vulnerability is reachable via local access without requiring user interaction. The attack results in high impact to availability with low impact to confidentiality and integrity of the vulnerable system.

## Affected products

- Intel Hyperscan before v5.4.2.1

## Timeline

- 2026-11-10: disclosed

## References

- [https://intel.com/content/www/us/en/security-center/advisory/intel-sa-01511.html](https://intel.com/content/www/us/en/security-center/advisory/intel-sa-01511.html)

## Related threats

- [Intel Hyperscan heap-based buffer overflow denial of service](https://junglewise.ai/threats/cve-2026-63540-heap-based-buffer-overflow-for-some-hyperscan-before-version-v5-4)
- [Intel Hyperscan out-of-bounds read in user applications](https://junglewise.ai/threats/cve-2026-40424-out-of-bounds-read-for-some-hyperscan-before-version-v5-4-2-1)
- [Intel Hyperscan multiple memory safety vulnerabilities](https://junglewise.ai/threats/cve-2026-40216-out-of-bounds-read-for-some-hyperscan-before-version-v5-4-2-1)
- [Intel Hyperscan untrusted pointer dereference DoS](https://junglewise.ai/threats/cve-2026-34489-untrusted-pointer-dereference-for-some-hyperscan-before-version)
- [Intel Hyperscan heap-based buffer overflow](https://junglewise.ai/threats/cve-2026-34017-heap-based-buffer-overflow-for-some-hyperscan-before-version-v5-4)