Is CVE-2026-39998 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-39998 being exploited in the wild.

How severe is CVE-2026-39998?

Informational severity, with a CVSS score of 5.8, published 19 June 2026.

Which products and versions are affected?

Apache APISIX 2.12.0 through 3.16.0.

Is there a fix for CVE-2026-39998?

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-2026-39998 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-39998?

Check whether you run Apache APISIX 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.

CVE-2026-39998: Apache APISIX identity spoofing in forward-auth plugin

CVE-2026-39998 · Severity: info · CVSS 5.8 · Published 2026-06-19

Apache APISIX is a cloud-native API gateway used to manage and secure web traffic. A security flaw in its authentication plugin allows an attacker to bypass identity checks by spoofing headers. This could allow unauthorized users to impersonate legitimate accounts and gain access to protected internal services.

Technologies: Apache APISIX. Vendors: Apache.

Quick answers

Is CVE-2026-39998 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-39998 being exploited in the wild.
How severe is CVE-2026-39998?: Informational severity, with a CVSS score of 5.8, published 19 June 2026.
Which products and versions are affected?: Apache APISIX 2.12.0 through 3.16.0.
Is there a fix for CVE-2026-39998?: 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-2026-39998 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-39998?: Check whether you run Apache APISIX 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

An improper input validation vulnerability exists in the Apache APISIX 'forward-auth' plugin due to missing header cleanup. When specific configurations are used, the plugin fails to properly sanitize or strip incoming headers that are later used for identity verification. A remote attacker with low privileges can exploit this by injecting malicious identity headers into their requests, effectively spoofing their identity to downstream services. The issue affects versions 2.12.0 through 3.16.0 and is resolved in version 3.17.0 (or 3.16.1 as per some advisory notes).

Affected products

Apache APISIX 2.12.0 through 3.16.0

Timeline

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

References

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