CVE-2026-34950

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Source
https://cve.org/CVERecord?id=CVE-2026-34950
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-34950.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-34950
Aliases
Published
2026-04-06T15:54:03.765Z
Modified
2026-08-12T03:51:43.516725548Z
Severity
  • 9.1 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N CVSS Calculator
Summary
fast-jwt has an incomplete fix for CVE-2023-48223: JWT Algorithm Confusion via Whitespace-Prefixed RSA Public Key
Details

fast-jwt provides fast JSON Web Token (JWT) implementation. In 6.1.0 and earlier, the publicKeyPemMatcher regex in fast-jwt/src/crypto.js uses a ^ anchor that is defeated by any leading whitespace in the key string, re-enabling the exact same JWT algorithm confusion attack that CVE-2023-48223 patched.

Database specific 
{
    "cwe_ids": [
        "CWE-327"
    ],
    "cna_assigner": "GitHub_M",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34950.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
e07b1fd23f02a47f1be677a21a4f07607b478e66
Database specific
Show details 
{
    "source": [
        "AFFECTED_FIELD",
        "CPE_RANGE"
    ],
    "cpe": "cpe:2.3:a:nearform:fast-jwt:*:*:*:*:*:node.js:*:*",
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "last_affected": "6.1.0"
        },
        {
            "fixed": "6.2.0"
        }
    ]
}

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

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-34950.json"