UBUNTU-CVE-2026-25537

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Source

https://ubuntu.com/security/CVE-2026-25537

Import Source

https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-25537.json

JSON Data

https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-25537

Upstream

CVE-2026-25537

Published

2026-02-04T22:15:00Z

Modified

2026-02-13T18:12:39.258254Z

Severity

5.5 (Medium) CVSS_V4 - 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 CVSS Calculator
7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N CVSS Calculator
Ubuntu - medium

Summary

[none]

Details

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: validatenbf = true), but the claim is not explicitly marked as required in requiredspec_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.

References

Affected packages

Ubuntu:24.04:LTS / rust-jsonwebtoken

Package

Name: rust-jsonwebtoken
Purl: pkg:deb/ubuntu/rust-jsonwebtoken@8.3.0-3?arch=source&distro=noble

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Affected versions

8.*

8.3.0-1

8.3.0-3

Ecosystem specific

{
    "binaries": [
        {
            "binary_name": "librust-jsonwebtoken-dev",
            "binary_version": "8.3.0-3"
        }
    ]
}

Database specific

source

"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-25537.json"

Ubuntu:25.10 / rust-jsonwebtoken