CVE-2021-41106
File reference keys leads to incorrect hashes on HMAC algorithms
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.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used 4.4
File reference keys leads to incorrect hashes on HMAC algorithms
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.
- Record
CVE-2021-41106- CVSS 3.1
- 4.4 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N - Weakness
- CWE-345
- Updated
- 2026-11-02
EUVDEUVD-2021-2000 4.4
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.
- Record
EUVD-2021-2000- CVSS 3.1
- 4.4 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-7322-jrq4-x5hf 4.4
File reference keys leads to incorrect hashes on HMAC algorithms
Impact
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, people are lead to believe that everything works properly.
Patches
All versions 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.
Workarounds
Use Lcobucci\JWT\Signer\Key\InMemory instead of Lcobucci\JWT\Signer\Key\LocalFileReference to create the instances of your keys:
-use Lcobucci\JWT\Signer\Key\LocalFileReference;
+use Lcobucci\JWT\Signer\Key\InMemory;
-$key = LocalFileReference::file(__DIR__ . '/public-key.pem');
+$key = InMemory::file(__DIR__ . '/public-key.pem');
- Record
GHSA-7322-jrq4-x5hf- CVSS 3.1
- 4.4 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N - Weakness
- CWE-345
- Updated
- 2026-11-02
NVD 4.4
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.
- Record
CVE-2021-41106- CVSS 3.1
- 4.4 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N - CVSS 3.1
- 3.3 Low
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N - CVSS 2.0
- 2.1 Low
AV:L/AC:L/Au:N/C:N/I:P/A:N - Weakness
- CWE-345
- Updated
- 2026-11-02
OSV 3.3
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.
- Record
CVE-2021-41106- CVSS 3.1
- 3.3 Low
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N - Updated
- 2026-11-02
OSVGHSA-7322-jrq4-x5hf 4.4
File reference keys leads to incorrect hashes on HMAC algorithms
Impact
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, people are lead to believe that everything works properly.
Patches
All versions 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.
Workarounds
Use Lcobucci\JWT\Signer\Key\InMemory instead of Lcobucci\JWT\Signer\Key\LocalFileReference to create the instances of your keys:
-use Lcobucci\JWT\Signer\Key\LocalFileReference;
+use Lcobucci\JWT\Signer\Key\InMemory;
-$key = LocalFileReference::file(__DIR__ . '/public-key.pem');
+$key = InMemory::file(__DIR__ . '/public-key.pem');
- Record
GHSA-7322-jrq4-x5hf- CVSS 3.1
- 4.4 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N - Weakness
- CWE-345
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
lcobucci/jwtPackagist | 3.4.0 up to 3.4.6 | 3.4.6 |
lcobucci/jwtPackagist | 4.0.0 up to 4.0.4 | 4.0.4 |
lcobucci/jwtPackagist | 4.1.0 up to 4.1.5 | 4.1.5 |
lcobucci/jwtPackagist | 3.4.0 up to 3.4.6, plus listed versions 3.4.13.4.23.4.33.4.43.4.5 | 3.4.6 |
lcobucci/jwtPackagist | 4.0.0 up to 4.0.4, plus listed versions 4.0.14.0.24.0.3 | 4.0.4 |
lcobucci/jwtPackagist | 4.1.0 up to 4.1.5, plus listed versions 4.1.14.1.24.1.34.1.4 | 4.1.5 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, products | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-41106 is a medium vulnerability (CVSS 4.4) in Golang-jwt Jwt, published September 28, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.21%, the 10th percentile. Fixed in lcobucci/jwt 3.4.6.
References
github.com/lcobucci/jwt/security/advisories/GHSA-7322-jrq4-x5hf
github.com/lcobucci/jwt/commit/8175de5b841fbe3fd97d2d49b3fc15c4ecb39a73
github.com/lcobucci/jwt/commit/c45bb8b961a8e742d8f6b88ef5ff1bd5cca5d01c
nvd.nist.gov/vuln/detail/CVE-2021-41106
github.com/FriendsOfPHP/security-advisories/blob/master/lcobucci/jwt/CVE-2021-41106.yaml
github.com/advisories/GHSA-7322-jrq4-x5hf
github.com/lcobucci/jwt