What’s Vulnerable › Vulnerabilities

CVE-2021-29455: Missing validation of JWT signature in `grassrootza/grassroot-platform`

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-04-19 · updated 2026-06-17
• Weakness: CWE-347

Description

Grassroot Platform is an application to make it faster, cheaper and easier to persistently organize and mobilize people in low-income communities. Grassroot Platform before master deployment as of 2021-04-16 did not properly verify the signature of JSON Web Tokens when refreshing an existing JWT. This allows to forge a valid JWT. The problem has been patched in version 1.3.1 by deprecating the JWT refresh function, which was an overdue deprecation regardless (the "refresh" flow is no longer used).

Affected products

• grassrootza grassroot-platform: before 1.3.1 — fixed in 1.3.1

How to fix

Upgrade to a fixed version: grassrootza grassroot-platform 1.3.1. Check the vendor advisory for mitigations.

References

• https://github.com/grassrootza/grassroot-platform/
• https://github.com/grassrootza/grassroot-platform/commit/a2e6e885f8183a066d938cf909fd813a7af7d67f
• https://github.com/grassrootza/grassroot-platform/security/advisories/GHSA-f65w-6xw8-6734
• https://github.com/grassrootza/grassroot-platform/
• https://github.com/grassrootza/grassroot-platform/commit/a2e6e885f8183a066d938cf909fd813a7af7d67f
• https://github.com/grassrootza/grassroot-platform/security/advisories/GHSA-f65w-6xw8-6734

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