CVE-2020-36223Network attack vector

Unauthenticated service crash via double-free

Published Jan 25, 2021 · Updated Aug 4, 2024

Out-of-bounds read in OpenLDAP slapd before 2.4.57 allows remote attackers to crash the directory server through a crafted Values Return Filter. In parseValuesReturnFilter, an error path frees op->o_vrFilter without nulling the pointer, allowing later cleanup to free it again. An unauthenticated network client can trigger the malformed control and interrupt directory service; no confidentiality or integrity impact is reported.

CVSS severity7.5
High
EPSS probability4.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in OpenLDAP slapd before 2.4.57 allows remote attackers to crash the directory server through a crafted Values Return Filter. In parseValuesReturnFilter, an error path frees op->o_vrFilter without nulling the pointer, allowing later cleanup to free it again. An unauthenticated network client can trigger the malformed control and interrupt directory service; no confidentiality or integrity impact is reported.

The record

CVE
CVE-2020-36223
Published
Jan 25, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-125, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 25, 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

7.5NetAppCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1499Endpoint Denial of Service

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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