CVE-2021-32800Network attack vector

Account access via unconditional 2FA setup exemption

Published Sep 7, 2021 · Updated Aug 3, 2024

Authentication bypass in Nextcloud Server before 20.0.12, 21.0.0 through 21.0.3, and 22.0.0 allows remote authenticated users to access accounts. TwoFactorMiddleware unconditionally exempted the login setup controller when a signed-in user needed a second factor, without checking whether an enabled provider still had to complete authentication. A password or access to a trusted WebAuthN device is required; bypassing the provider check grants the victim account's existing access but does not add privileges.

CVSS severity8.1
High
EPSS probability1.80%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Authentication bypass in Nextcloud Server before 20.0.12, 21.0.0 through 21.0.3, and 22.0.0 allows remote authenticated users to access accounts. TwoFactorMiddleware unconditionally exempted the login setup controller when a signed-in user needed a second factor, without checking whether an enabled provider still had to complete authentication. A password or access to a trusted WebAuthN device is required; bypassing the provider check grants the victim account's existing access but does not add privileges.

The record

CVE
CVE-2021-32800
Published
Sep 7, 2021
Updated
Aug 3, 2024
Vendor
Nextcloud GmbH
Product
Nextcloud Security Advisories
Classifications
CWE-304, T1078
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 7, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=< 20.0.12
  2. Affected versionversion=>= 21.0.0, < 21.0.4
  3. Affected versionversion=>= 22.0.0, < 22.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Nextcloud GmbH · Nextcloud Security Advisoriesversion=< 20.0.12; version=>= 21.0.0, < 21.0.4; version=>= 22.0.0, < 22.1.0

Published CVSS scores

8.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

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-304Missing Critical Step in 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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo