# CVE-2026-39999: Apache APISIX authentication bypass in jwt-auth plugin

Source: https://junglewise.ai/threats/cve-2026-39999-apache-apisix-authentication-bypass-in-jwt-auth-plugin  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-19. Updated: 2026-06-21  
License: CC BY 4.0 with a link back

CVE-2026-39999 · Severity: info · CVSS 7 · Published 2026-06-19

Apache APISIX, a popular API gateway used to manage and secure web traffic, contains a vulnerability in its JWT authentication plugin. An attacker can exploit specific configurations to bypass security checks and gain unauthorized access to protected internal services. This could lead to the exposure of sensitive data or unauthorized operations within a company's infrastructure.

## Quick answers

**Is CVE-2026-39999 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-39999 being exploited in the wild.

**How severe is CVE-2026-39999?** Informational severity, with a CVSS score of 7, published 19 June 2026.

**Which products and versions are affected?** Apache APISIX 2.2 through 3.16.0.

**Is there a fix for CVE-2026-39999?** 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-2026-39999 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-39999?** Check whether anything you run is named in the advisory. 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

An authentication bypass vulnerability exists in Apache APISIX versions 2.2 through 3.16.0 within the jwt-auth plugin. The flaw is characterized as an 'Authentication Bypass by Spoofing' (CWE-290), specifically involving JWT algorithm confusion. When certain configurations are present, an attacker can craft a malicious token that the gateway incorrectly validates, allowing them to bypass authentication entirely. This is a network-reachable vulnerability that requires no prior privileges. Users are advised to upgrade to version 3.17.0 (or 3.16.1 as noted in some advisory text) to remediate the issue.

## Affected products

- Apache APISIX 2.2 through 3.16.0

## Timeline

- 2026-06-19: disclosed
- 2026-06-19: advisory

## References

- [https://lists.apache.org/thread/nfopt8cnxd3k0rs1oxtr7lzxrdw4mojq](https://lists.apache.org/thread/nfopt8cnxd3k0rs1oxtr7lzxrdw4mojq)
- [http://www.openwall.com/lists/oss-security/2026/06/19/5](http://www.openwall.com/lists/oss-security/2026/06/19/5)