Apache APISIX: forward auth plugin allows header injection

published 2026-04-14 6 mo ago modified 2026-10-26 13 d ago also BIT-apisix-2026-31908 , EUVD-2026-22225

cvss: 9.1; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 44%
public exploits: 0; none known

Header injection vulnerability in Apache APISIX.

The attacker can take advantage of certain configuration in forward-auth plugin to inject malicious headers. This issue affects Apache APISIX: from 2.12.0 through 3.15.0.

Users are recommended to upgrade to version 3.16.0, which fixes the issue.

Patch / fix

fixed in 1

bitnami apisix 3.16.0

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: total
Assessed: 6 mo ago (2026-04-16)

Exploit prediction

0.52% chance of exploitation in the next 30 days, higher than 44% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CISA ADP	3.1	9.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CNA	3.1	9.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
OSV	3.1	9.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected packages

ecosystem	package	affected	fixed in
bitnami	apisix	>=2.12.0, <3.16.0	3.16.0

Affected products

Apache Software Foundation Apache APISIX

Classification

Weakness

CWE-75 Failure to Sanitize Special Elements into a Different Plane

References

lists.apache.org /thread/sob643s5lztov7x579j8o0c444t36n6b
vendor-advisory, mailing-list, advisory
openwall.com /lists/oss-security/2026/04/14/3
mailing-list, third-party-advisory, advisory
nvd.nist.gov /vuln/detail/CVE-2026-31908
web

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary