CVE-2026-56306Public exploitNetwork attack vector

Authenticated scope bypass via falsy subkey parsing

Published Jun 22, 2026 · Updated Jun 22, 2026

Improper input validation in Capgo before 12.128.2 allows remote authenticated users to bypass subkey scope restrictions via HTTP headers. getSubkeyId converts x-limited-key-id with Number(), and middlewareKey treats NaN and zero as false, skipping the restricted-subkey branch. A valid API key and control of the request header are required; affected requests execute under the broader main-key context.

CVSS severity5.3
Medium
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Capgo before 12.128.2 allows remote authenticated users to bypass subkey scope restrictions via HTTP headers. getSubkeyId converts x-limited-key-id with Number(), and middlewareKey treats NaN and zero as false, skipping the restricted-subkey branch. A valid API key and control of the request header are required; affected requests execute under the broader main-key context.

The record

CVE
CVE-2026-56306
Published
Jun 22, 2026
Updated
Jun 22, 2026
Vendor
Capgo
Product
Capgo
Classifications
CWE-178, CWE-20, CWE-235, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 22, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=0 <12.128.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Capgo · Capgoversion=0 <12.128.2

Published CVSS scores

6.4VulnCheckCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
5.3VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-178Improper Handling of Case Sensitivity
CWE-20Improper Input Validation
CWE-235Improper Handling of Extra Parameters
T1190Exploit Public-Facing Application

Public exploit references

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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