CVE-2021-41106 File reference keys leads to incorrect hashes on HMAC algorithms
Users relying on file path references for HMAC keys in this JWT library may inadvertently use the path string as the secret, allowing token forgery.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2021-41106?
CVE-2021-41106 is a medium-severity vulnerability in lcobucci jwt, published on 28 Sep 2021. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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.
Weakness: CWE-345
Which versions are affected by CVE-2021-41106?
6 open source packages ship an affected version, including lcobucci/jwt. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
lcobucci/jwt Packagist | From 3.4.0 | 3.4.6 |
lcobucci/jwt Packagist | From 3.4.0 | 3.4.6 |
lcobucci/jwt Packagist | From 4.0.0 | 4.0.4 |
lcobucci/jwt Packagist | From 4.0.0 | 4.0.4 |
lcobucci/jwt Packagist | From 4.1.0 | 4.1.5 |
lcobucci/jwt Packagist | From 4.1.0 | 4.1.5 |
Products include Lcobucci Jwt.
How do I fix CVE-2021-41106?
Upgrade lcobucci/jwt to a fixed version for your release line: 3.4.6, 4.0.4 or 4.1.5.
Is CVE-2021-41106 being exploited?
There is no known exploitation of CVE-2021-41106 in the wild and no public exploit code.
Sources
Also known as GHSA-7322-jrq4-x5hf.