CVE-2026-45021Network attack vector

Admin credential theft via cross-origin localhost trust

Published May 28, 2026 · Updated May 28, 2026

Cross-origin access in Kong Inc. Kuma affected releases allows remote attackers to read and use control-plane admin credentials. The API server reflects an arbitrary Origin while LocalhostIsAdmin promotes loopback browser requests, exposing the admin JWT and signing keys. Exploitation requires default settings, browser-local control-plane reachability, and an operator visiting attacker-controlled JavaScript.

CVSS severity5.1
Medium
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-origin access in Kong Inc. Kuma affected releases allows remote attackers to read and use control-plane admin credentials. The API server reflects an arbitrary Origin while LocalhostIsAdmin promotes loopback browser requests, exposing the admin JWT and signing keys. Exploitation requires default settings, browser-local control-plane reachability, and an operator visiting attacker-controlled JavaScript.

The record

CVE
CVE-2026-45021
Published
May 28, 2026
Updated
May 28, 2026
Vendor
Kong Inc.
Product
Kuma
Classifications
CWE-942, CWE-346, T1528
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 28, 2026CVE publishedPublication date reported by the CVE source.
  2. May 28, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 2.11.0, < 2.11.13
  2. Affected versionversion=>= 2.12.0, < 2.12.10
  3. Affected versionversion=>= 2.13.0, < 2.13.5
  4. Affected versionversion=< 2.7.25
  5. Affected versionversion=>= 2.9.0, < 2.9.15

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Kong Inc. · Kumaversion=>= 2.11.0, < 2.11.13; version=>= 2.12.0, < 2.12.10; version=>= 2.13.0, < 2.13.5; version=< 2.7.25; version=>= 2.9.0, < 2.9.15

Published CVSS scores

5.1GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-942Permissive Cross-domain Security Policy with Untrusted Domains
CWE-346Origin Validation Error
T1528Steal Application Access Token

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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