CVE-2020-36659Network attack vector

LDAP server impersonation via disabled certificate validation

Published Jan 27, 2023 · Updated Apr 3, 2025

Improper certificate validation in Apache::Session::Browseable before 1.3.6 allows remote attackers to impersonate LDAP servers. LDAP.pm creates LDAPS and StartTLS connections without requiring peer-certificate verification, inheriting Net::LDAP defaults that do not validate the server certificate. Exploitation requires a man-in-the-middle position on the LDAP path and exposes session-backend traffic to interception or modification.

CVSS severity8.1
High
EPSS probability0.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper certificate validation in Apache::Session::Browseable before 1.3.6 allows remote attackers to impersonate LDAP servers. LDAP.pm creates LDAPS and StartTLS connections without requiring peer-certificate verification, inheriting Net::LDAP defaults that do not validate the server certificate. Exploitation requires a man-in-the-middle position on the LDAP path and exposes session-backend traffic to interception or modification.

The record

CVE
CVE-2020-36659
Published
Jan 27, 2023
Updated
Apr 3, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-295, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 27, 2023CVE publishedPublication date reported by the CVE source.
  2. Apr 3, 2025Record 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

8.1UbuntuCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
8.1CISA-ADPCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
8.1NIST NVDCVSS:3.1/AV:N/AC:H/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.

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

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-295Improper Certificate Validation
T1557Adversary-in-the-Middle

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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