CVE-2021-32631Public exploitNetwork attack vector

Authenticated access bypass via unsigned JWT acceptance

Published Jul 26, 2021 · Updated Aug 3, 2024

JWT authentication bypass in NIMBLE Project Common before 3b96cb0293d3443b870351945f41d7d55cb34b53 allows remote authenticated users to forge tokens. ValidationUtil passes received JWTs to the generic parse method, which accepts two-part unsigned tokens instead of requiring a signed three-part JWS. An attacker must reach a NIMBLE service that consumes this utility; a forged token can then impersonate authenticated claims and bypass access checks.

CVSS severity6.5
Medium
EPSS probability1.09%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

JWT authentication bypass in NIMBLE Project Common before 3b96cb0293d3443b870351945f41d7d55cb34b53 allows remote authenticated users to forge tokens. ValidationUtil passes received JWTs to the generic parse method, which accepts two-part unsigned tokens instead of requiring a signed three-part JWS. An attacker must reach a NIMBLE service that consumes this utility; a forged token can then impersonate authenticated claims and bypass access checks.

The record

CVE
CVE-2021-32631
Published
Jul 26, 2021
Updated
Aug 3, 2024
Vendor
NIMBLE Project
Product
Common
Classifications
CWE-290, T1606
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 26, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=< 3b96cb0293d3443b870351945f41d7d55cb34b53

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

NIMBLE Project · Commonversion=< 3b96cb0293d3443b870351945f41d7d55cb34b53

Published CVSS scores

4.0NISTAV:N/AC:L/Au:S/C:N/I:P/A:N
6.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
6.5NISTCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-290Authentication Bypass by Spoofing
T1606Forge Web Credentials

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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