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Medium, CVSS 4.4

File reference keys leads to incorrect hashes on HMAC algorithms

CVE-2021-41106GHSA-7322-jrq4-x5hf

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (lcobucci/jwt 4.1.5, 4.0.4, 3.4.6), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

  • Packagist lcobucci/jwt

    Affected
    >= 3.4.0, < 3.4.6>= 4.0.0, < 4.0.4>= 4.1.0, < 4.1.5
    Fixed in
    4.1.5, 3.4.6, 4.0.4

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS
4.4 · CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
EPSS
  • CVE-2021-41106: 0.21% estimated exploitation activity in the next 30 days; percentile 10.58 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

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:

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 1 · created ·

    Published from ghsa record GHSA-7322-jrq4-x5hf

Agent brief

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2021-41106

Advisory: File reference keys leads to incorrect hashes on HMAC algorithms
IDs: CVE-2021-41106, GHSA-7322-jrq4-x5hf
Record: https://patchnext.com/advisories/cve-2021-41106 (revision 1, source checked 26 Oct 2026, 14:15 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 4.4)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: lcobucci/jwt 4.1.5, 4.0.4, 3.4.6. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist lcobucci/jwt: affected >= 3.4.0, < 3.4.6; >= 4.0.0, < 4.0.4; >= 4.1.0, < 4.1.5; fixed in 4.1.5, 3.4.6, 4.0.4

## Suggested inspection (read-only)
- Packagist lcobucci/jwt: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on lcobucci/jwt.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-7322-jrq4-x5hf (GitHub-reviewed advisory GHSA-7322-jrq4-x5hf lists affected ranges: Packagist lcobucci/jwt >=3.4.0 =4.0.0 =4.1.0 <4.1.5)

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