CVE-2026-39998

Name: CVE-2026-39998
Creator: NVD / NIST
Published: 2026-06-19T14:16:21.823+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.8/10EPSS 0.40%

Last modified Jun 23, 2026

CVE-2026-39998 is a medium-severity vulnerability rated 5.8/10 on the CVSS scale. 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.. EPSS estimates a 0.40% chance of exploitation in the next 30 days.

Description

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 3.1

8.8/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS 4.0

5.8/10

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability

0.40%

32.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-20

Affected Software

Vendor	Product	Versions
Apache	Apisix	>= 2.12.0, < 3.17.0

References

https://lists.apache.org/thread/vgkvy396010d7g6m0jrn4d3hjf2svlvvVendor Advisory, Mailing List
http://www.openwall.com/lists/oss-security/2026/06/19/4Third Party Advisory

Timeline

Published: Jun 19, 2026
Last Modified: Jun 23, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-39998?

How severe is CVE-2026-39998?

CVE-2026-39998 has a CVSS score of 5.8/10 (MEDIUM severity). The EPSS model estimates a 0.40% probability of exploitation in the next 30 days.

How do I fix CVE-2026-39998?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-39998?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST