How severe is CVE-2026-39998?

CVE-2026-39998 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-39998 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (32nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-39998?

CVE-2026-39998 affects Apache Apisix. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-39998?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-39998 have an EU (EUVD) identifier?

Yes. CVE-2026-39998 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38011.

When was CVE-2026-39998 published?

CVE-2026-39998 was published on 2026-06-19 and last updated on 2026-06-23.

CVE-2026-39998

CVE-2026-39998 is a high-severity vulnerability in Apache Apisix with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-20.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v4: 5.8
EPSS exploit prediction: 0% (32nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-38011
Weakness: CWE-20
Affected product: Apache Apisix
Published: 2026-06-19
Last modified: 2026-06-23

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.

Frequently asked questions

What is CVE-2026-39998?: 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.
How severe is CVE-2026-39998?: CVE-2026-39998 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-39998 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (32nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-39998?: CVE-2026-39998 affects Apache Apisix. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-39998?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-39998 have an EU (EUVD) identifier?: Yes. CVE-2026-39998 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38011.
When was CVE-2026-39998 published?: CVE-2026-39998 was published on 2026-06-19 and last updated on 2026-06-23.

References

Affected products (1)

cpe:2.3:a:apache:apisix:*:*:*:*:*:*:*:*

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