CVE-2021-35943Network attack vector

Authentication bypass via accepted empty-password directory bind

Published Sep 29, 2021 · Updated Aug 4, 2024

Improper authentication in Couchbase Server 6.5.x and 6.6.0 through 6.6.2 allows remote attackers to authenticate with an empty password. The Cluster Manager accepts an LDAP or Active Directory unauthenticated bind as successful external-user authentication instead of rejecting the empty password. Exploitation requires external authentication and a directory server configured to permit insecure unauthenticated binds, granting the external user's assigned access.

CVSS severity9.8
Critical
EPSS probability1.07%
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 Couchbase Server 6.5.x and 6.6.0 through 6.6.2 allows remote attackers to authenticate with an empty password. The Cluster Manager accepts an LDAP or Active Directory unauthenticated bind as successful external-user authentication instead of rejecting the empty password. Exploitation requires external authentication and a directory server configured to permit insecure unauthenticated binds, granting the external user's assigned access.

The record

CVE
CVE-2021-35943
Published
Sep 29, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-287, T1078
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 29, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
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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