CVE-2026-107720

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Source
https://cve.org/CVERecord?id=CVE-2026-107720
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-107720.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-107720
Aliases
Published
2026-10-08T21:44:06Z
Modified
2026-10-09T10:46:05Z
Severity
  • 7.4 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N CVSS Calculator
Summary
fast-jwt: createVerifier accepts unsigned JWTs when key is '' or null and algorithms is explicitly set
Details

fast-jwt provides fast JSON Web Token (JWT) implementation. Prior to 6.3.1, fast-jwt createVerifier accepts an unsigned JWT when key is an empty string or null and algorithms is a non-empty allowlist. Falsy synchronous keys bypass prepareKeyOrSecret, allowedAlgorithms remains active, hasKey is false, and the empty signature avoids the verifySignature gate. An attacker can therefore submit a token containing arbitrary claims without possessing a signing key, resulting in authentication or authorization bypass. Claim validators still run, and non-empty keys, an empty key without algorithms, and the async key resolver path do not have this behavior. This issue is fixed in version 6.3.1.

Database specific 
{
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
        "CWE-20",
        "CWE-347"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/107xxx/CVE-2026-107720.json"
}
References

Affected packages

Git / github.com/nearform/fast-jwt

Affected ranges

Type
GIT
Repo
https://github.com/nearform/fast-jwt
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
865c52262f39234a9b97524eb7f4821cf6d921ad
Database specific
Show details 
{
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "fixed": "6.3.1"
        }
    ],
    "source": "AFFECTED_FIELD"
}

Affected versions

v0.*
v0.1.0
v0.1.1
v0.2.0
v0.3.0
v0.3.1
v0.4.0
v0.4.1
v0.4.2
v0.5.0
v0.5.1
v1.*
v1.0.0
v1.1.0
v1.1.1
v1.1.2
v1.1.3
v1.2.0
v1.3.0
v1.3.2
v1.4.0
v1.4.1
v1.5.0
v1.5.1
v1.5.2
v1.5.3
v1.5.4
v1.6.0
v1.6.1
v1.7.0
v1.7.1
v1.7.2
v2.*
v2.0.0
v6.*
v6.1.0
v6.2.0
v6.2.1
v6.2.2
v6.2.3
v6.2.4
v6.3.0

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-107720.json"