# CVE-2026-26081: HAProxy missing length check in NEW_TOKEN format handling

Source: https://junglewise.ai/threats/cve-2026-26081-haproxy-missing-length-check-in-new-token-format-handling  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-20. Updated: 2026-07-20  
License: CC BY 4.0 with a link back

CVE-2026-26081 · Severity: medium · CVSS 4.8 · Published 2026-07-20

HAProxy is a high-performance load balancer used to distribute web traffic and ensure application availability. A vulnerability in how it handles certain network tokens could allow an attacker to send specially crafted data packets that crash the service. This would result in a service outage, preventing legitimate users from accessing the applications protected by HAProxy.

Vendors: [HAProxy](https://junglewise.ai/threats/vendors/haproxy).

## Quick answers

**Is CVE-2026-26081 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-26081 being exploited in the wild.

**How severe is CVE-2026-26081?** Medium severity, with a CVSS score of 4.8, published 20 July 2026.

**Which products and versions are affected?** HAProxy Community Edition 3.0 before 3.0.12, 3.1 before 3.1.14, 3.2 before 3.2.12, 3.3 before 3.3.3.

**Is there a fix for CVE-2026-26081?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-26081 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-26081?** Check whether you run HAProxy ALOHA, HAProxy Community Edition or HAProxy Enterprise 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.

## Technical details

A vulnerability exists in HAProxy versions 3.0 through 3.3 (before 3.3.3) due to an improper handling of the length parameter (CWE-130) within the NEW_TOKEN format, specifically affecting QUIC parsing. An attacker can exploit this by sending specially crafted network packets to the HAProxy instance. Successful exploitation can lead to a process crash, resulting in a denial-of-service (DoS) condition. The vulnerability has been addressed in versions 3.0.12, 3.1.14, 3.2.12, and 3.3.3.

## Affected products

- HAProxy HAProxy Community Edition 3.0 before 3.0.12, 3.1 before 3.1.14, 3.2 before 3.2.12, 3.3 before 3.3.3
- HAProxy HAProxy Enterprise
- HAProxy ALOHA

## Timeline

- 2026-02-12: advisory: HAProxy project mentions the vulnerability in news updates
- 2026-07-20: disclosed: CVE published to NVD dataset

## References

- [https://git.haproxy.org/?p=haproxy-3.2.git;a=commit;h=4765277f4f915baac2d57db63538ff0a59966deb](https://git.haproxy.org/?p=haproxy-3.2.git;a=commit;h=4765277f4f915baac2d57db63538ff0a59966deb)
- [https://www.haproxy.org/](https://www.haproxy.org/)

## Related threats

- [HAProxy denial of service via varint mishandling in QUIC parsing](https://junglewise.ai/threats/cve-2026-26080-haproxy-denial-of-service-via-varint-mishandling-in-quic-parsing)