CVE-2019-4540Network attack vector

Remote information decryption via undisclosed weak cryptography

Published Feb 4, 2020 · Updated Sep 16, 2024

Weak cryptography in IBM Security Directory Server 6.4.0 allows remote attackers to decrypt highly sensitive information over a network. IBM identifies only weaker-than-expected cryptographic algorithms and has not disclosed the affected protocol, cipher, component, or key-handling operation. Exploitation requires no authentication or user interaction but has high complexity, and the documented impact is limited to confidentiality.

CVSS severity5.9
Medium
EPSS probability0.79%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Weak cryptography in IBM Security Directory Server 6.4.0 allows remote attackers to decrypt highly sensitive information over a network. IBM identifies only weaker-than-expected cryptographic algorithms and has not disclosed the affected protocol, cipher, component, or key-handling operation. Exploitation requires no authentication or user interaction but has high complexity, and the documented impact is limited to confidentiality.

The record

CVE
CVE-2019-4540
Published
Feb 4, 2020
Updated
Sep 16, 2024
Vendor
IBM
Product
IBM Security Directory Server
Classifications
CWE-327
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 4, 2020CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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?

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

  1. Affected versionversion=6.4.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

IBM · IBM Security Directory Serverversion=6.4.0

Published CVSS scores

5.0NVDAV:N/AC:L/Au:N/C:P/I:N/A:N
5.9IBM CorporationCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-327Use of a Broken or Risky Cryptographic Algorithm

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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