CVE-2021-21329Network attack vector

MFA bypass via unconditional token issuance

Published Mar 8, 2021 · Updated Aug 3, 2024

Improper authentication in RACTF Core affected revisions allows remote attackers with valid passwords to bypass MFA and obtain session tokens. The MFA login view falls through to an unconditional issue_token(user) return after a submitted one-time code fails validation, rather than returning HTTP 401. Exploitation requires valid account credentials for an MFA-enabled user and grants that user's application access without the second factor.

CVSS severity8.7
High
EPSS probability1.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authentication in RACTF Core affected revisions allows remote attackers with valid passwords to bypass MFA and obtain session tokens. The MFA login view falls through to an unconditional issue_token(user) return after a submitted one-time code fails validation, rather than returning HTTP 401. Exploitation requires valid account credentials for an MFA-enabled user and grants that user's application access without the second factor.

The record

CVE
CVE-2021-21329
Published
Mar 8, 2021
Updated
Aug 3, 2024
Vendor
Really Awesome CTF
Product
core
Classifications
CWE-287, T1078
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 8, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>c57a4d186bfc586ad3edfe4dcba9f11efbf22f09, < cebb67bd16a8296121201805332365ffccb29638

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Really Awesome CTF · coreversion=>c57a4d186bfc586ad3edfe4dcba9f11efbf22f09, < cebb67bd16a8296121201805332365ffccb29638

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
8.7GitHubCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-287Improper Authentication
T1078Valid Accounts

Public exploit references

No public exploit references are available in this record.

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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