CVE-2026-56306
Received Received - Intake
Weak Header Parsing in Capgo Allows API Key Bypass

Publication date: 2026-06-22

Last updated on: 2026-06-22

Assigner: VulnCheck

Description
Capgo before 12.128.2 contains a weak parsing vulnerability in the x-limited-key-id header that allows attackers to bypass subkey enforcement by submitting malformed values, zero, or duplicate headers that result in NaN or falsy values. Remote attackers can manipulate the x-limited-key-id header to disable limited key scoping and execute requests using the main API key context instead of restricted subkey permissions.
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Meta Information
Published
2026-06-22
Last Modified
2026-06-22
Generated
2026-06-23
AI Q&A
2026-06-23
EPSS Evaluated
N/A
NVD
CVE-2026-56306
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
capgo capgo to 12.128.2 (exc)
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Exploitability
CWE
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KEV
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CWE ID Description
CWE-20 The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
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Executive Summary

This vulnerability exists in Capgo versions before 12.128.2 and involves a weak parsing issue in the x-limited-key-id header.

Attackers can submit malformed, zero, or duplicate x-limited-key-id headers that cause the system to interpret these values as NaN (Not a Number) or falsy.

This allows remote attackers to bypass subkey enforcement, effectively disabling limited key scoping.

As a result, attackers can execute requests using the main API key context instead of the restricted permissions intended by subkeys.

Impact Analysis

This vulnerability can allow attackers to bypass security restrictions imposed by subkey permissions.

By exploiting the weak parsing of the x-limited-key-id header, attackers can gain unauthorized access to perform actions with the full privileges of the main API key.

This can lead to unauthorized operations, potential data exposure, or manipulation within systems using Capgo.

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