CVE-2021-41106 json
File reference keys leads to incorrect hashes on HMAC algorithms
published 2021-09-28 5 y ago modified 2026-07-08 4 mo ago also GHSA-7322-jrq4-x5hf , EUVD-2021-2000
- cvss
- 4.4
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 10%
- public exploits
- 0
- none known
Summary
JWT is a library to work with JSON Web Token and JSON Web Signature. Prior to versions 3.4.6, 4.0.4, and 4.1.5, users of HMAC-based algorithms (HS256, HS384, and HS512) combined with `Lcobucci\JWT\Signer\Key\LocalFileReference` as key are having their tokens issued/validated using the file path as hashing key - instead of the contents. The HMAC hashing functions take any string as input and, since users can issue and validate tokens, users are lead to believe that everything works properly. Versions 3.4.6, 4.0.4, and 4.1.5 have been patched to always load the file contents, deprecated the `Lcobucci\JWT\Signer\Key\LocalFileReference`, and suggest `Lcobucci\JWT\Signer\Key\InMemory` as the alternative. As a workaround, use `Lcobucci\JWT\Signer\Key\InMemory` instead of `Lcobucci\JWT\Signer\Key\LocalFileReference` to create the instances of one's keys.
Patch / fix
- packagist lcobucci/jwt 3.4.6, 4.0.4, 4.1.5
- lcobucci jwt 3.4.6, 4.0.4, 4.1.5
Exploit prediction
0.21% chance of exploitation in the next 30 days, higher than 10% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 4.4 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N |
| NVD | 3.1 | 3.3 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N |
| NVD | 2.0 | 2.1 | AV:L/AC:L/Au:N/C:N/I:P/A:N |
| GitHub | 3.1 | 4.4 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| packagist | lcobucci/jwt | >=3.4.0, <3.4.6 >=4.0.0, <4.0.4 >=4.1.0, <4.1.5 |
3.4.6 4.0.4 4.1.5 |
Affected products
- lcobucci jwt
Classification
- Weakness
-
- CWE-345 Insufficient Verification of Data Authenticity
References
-
github.com
/lcobucci/jwt/commit/8175de5b841fbe3fd97d2d49b3fc15c4ecb39a73
web, patch, third-party-advisory
-
github.com
/lcobucci/jwt/commit/c45bb8b961a8e742d8f6b88ef5ff1bd5cca5d01c
web, patch, third-party-advisory
-
github.com
/lcobucci/jwt/security/advisories/GHSA-7322-jrq4-x5hf
web, patch, third-party-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2021-41106
advisory
-
github.com
/FriendsOfPHP/security-advisories/blob/master/lcobucci/jwt/CVE-2021-41106.yaml
web
-
github.com
/lcobucci/jwt
package
Sources
- CVE List CVE-2021-41106
- GitHub Advisory GHSA-7322-jrq4-x5hf
- NVD CVE-2021-41106
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