jsonwebtoken is a JWT lib in rust. Prior to version 10.3.0, there is a Type Confusion vulnerability in jsonwebtoken, specifically, in its claim validation logic. When a standard claim (such as nbf or exp) is provided with an incorrect JSON type (Like a String instead of a Number), the library’s internal parsing mechanism marks the claim as “FailedToParse”. Crucially, the validation logic treats this “FailedToParse” state identically to “NotPresent”. This means that if a check is enabled (like: validate_nbf = true), but the claim is not explicitly marked as required in required_spec_claims, the library will skip the validation check entirely for the malformed claim, treating it as if it were not there. This allows attackers to bypass critical time-based security restrictions (like “Not Before” checks) and commit potential authentication and authorization bypasses. This issue has been patched in version 10.3.0.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact Low

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
Keats jsonwebtoken affected
Version Status Constraints
< 10.3.0 affected —

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Project Subscriptions

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-h395-gr6q-cpjc jsonwebtoken has Type Confusion that leads to potential authorization bypass
Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/Keats/jsonwebtoken/commit/abbc3076742c4161347bc6b8bf4aa5eb86e1dc01 cve-icon cve-icon
https://github.com/Keats/jsonwebtoken/security/advisories/GHSA-h395-gr6q-cpjc cve-icon cve-icon
History

Wed, 04 Feb 2026 21:45:00 +0000

Type Values Removed Values Added
Description jsonwebtoken is a JWT lib in rust. Prior to version 10.3.0, there is a Type Confusion vulnerability in jsonwebtoken, specifically, in its claim validation logic. When a standard claim (such as nbf or exp) is provided with an incorrect JSON type (Like a String instead of a Number), the library’s internal parsing mechanism marks the claim as “FailedToParse”. Crucially, the validation logic treats this “FailedToParse” state identically to “NotPresent”. This means that if a check is enabled (like: validate_nbf = true), but the claim is not explicitly marked as required in required_spec_claims, the library will skip the validation check entirely for the malformed claim, treating it as if it were not there. This allows attackers to bypass critical time-based security restrictions (like “Not Before” checks) and commit potential authentication and authorization bypasses. This issue has been patched in version 10.3.0.
Title jsonwebtoken has Type Confusion that leads to potential authorization bypass
Weaknesses CWE-843
References
Metrics cvssV4_0

{'score': 5.5, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-02-04T21:31:53.511Z

Reserved: 2026-02-02T19:59:47.374Z

Link: CVE-2026-25537

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-02-04T22:15:59.807

Modified: 2026-02-04T22:15:59.807

Link: CVE-2026-25537

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses