CVE-2026-39998 PUBLISHED

Apache APISIX: Identity Injection via forward-auth Plugin Missing Header Cleanup

Assigner: apache
Reserved: 08.04.2026 Published: 19.06.2026 Updated: 19.06.2026

Improper Input Validation vulnerability in Apache APISIX.

The attacker can take advantage of certain configuration in forward-auth plugin to spoof identity headers. This issue affects Apache APISIX: from 2.12.0 through 3.16.0.

Users are recommended to upgrade to version 3.17.0, which fixes the issue.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H
CVSS Score: 5.8

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	None	Confidentiality	High
Attack Complexity	Low	Integrity	None	Integrity	High
Attack Requirements	Present	Availability	None	Availability	High
Privileges Required	Low
User Interaction	None

CVSS 4.0

Product Status

Vendor	Apache Software Foundation
Product	Apache APISIX
Versions	Default: unaffected affected from 2.12.0 to 3.16.0 (incl.)

Credits

Fernando Mecozzi reporter

References

https://lists.apache.org/thread/vgkvy396010d7g6m0jrn4d3hjf2svlvv

Problem Types

CWE-20 Improper Input Validation CWE