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CVE-2026-39998

33
FAUCET Score

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.

First published: Jun 19, 2026Last modified: Jun 19, 2026

Impacted Technologies

VendorProductVersion(s)CPE
>= 2.12.0, < 3.17.0CPE matchmatch criteria
cpe:2.3:a:apache:apisix:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 4.0

5.8MEDIUM

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

Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
PRESENT
Privileges Required
LOW
User Interaction
NONE
VS Confidentiality
NONE
VS Integrity
NONE
VS Availability
NONE
SS Confidentiality
HIGH
SS Integrity
HIGH
SS Availability
HIGH
Exploit Maturity
NOT_DEFINED
CvssVersion
4.0

Exploit Intelligence

EPSS Score
0.40%
Probability of exploitation in next 30 days
EPSS Percentile
32.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0040 is in the 21st percentile among its peer group of 17,829 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.3 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Vendor Patches (1)

apachevendor investigatingvia vendor_rss
View patch

Vendor Advisories (1)

apacheapache:www.mail-archive.com/[email protected]/msg11267.html

CVE-2026-39998: Apache APISIX: Identity Injection via forward-auth Plugin Missing Header Cleanup

Jun 19, 2026

References

openwall.com / lists/oss-security/2026/06/19/4
Third Party Advisory
lists.apache.org / thread/vgkvy396010d7g6m0jrn4d3hjf2svlvv
Vendor AdvisoryMailing List