CVE-2021-3480Network attack vector

Directory server crash via malformed Binding DN

Published May 20, 2021 · Updated Aug 3, 2024

NULL pointer dereference in slapi-nis before 0.56.7 allows remote attackers to crash the 389 Directory Server via a crafted Binding DN. The plug-in's bind-DN parser dereferences a NULL pointer while processing the malformed name. An unauthenticated LDAP bind request is sufficient to terminate the directory-server process, interrupting directory service availability.

CVSS severity7.5
High
EPSS probability1.70%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in slapi-nis before 0.56.7 allows remote attackers to crash the 389 Directory Server via a crafted Binding DN. The plug-in's bind-DN parser dereferences a NULL pointer while processing the malformed name. An unauthenticated LDAP bind request is sufficient to terminate the directory-server process, interrupting directory service availability.

The record

CVE
CVE-2021-3480
Published
May 20, 2021
Updated
Aug 3, 2024
Vendor
Slapi-nis Project
Product
slapi-nis
Classifications
CWE-476, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 20, 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=slapi-nis 0.56.7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Slapi-nis Project · slapi-nisversion=slapi-nis 0.56.7

Published CVSS scores

7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NVDAV:N/AC:L/Au:N/C:N/I:N/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.

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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-476NULL Pointer Dereference
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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