CVE-2020-4089Network attack vector

File disclosure via crafted mailto links

Published Jun 26, 2020 · Updated Aug 4, 2024

Information disclosure in HCL Notes 9, 10, and 11 allows remote attackers to read local or network files through a crafted mailto link. HCL has not disclosed which mailto-processing component accepts the file reference or how it packages the referenced content for transmission. A user must activate attacker-controlled content, after which files accessible to that user's account can be disclosed to a third party.

CVSS severity6.5
Medium
EPSS probability1.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in HCL Notes 9, 10, and 11 allows remote attackers to read local or network files through a crafted mailto link. HCL has not disclosed which mailto-processing component accepts the file reference or how it packages the referenced content for transmission. A user must activate attacker-controlled content, after which files accessible to that user's account can be disclosed to a third party.

The record

CVE
CVE-2020-4089
Published
Jun 26, 2020
Updated
Aug 4, 2024
Vendor
HCL Software
Product
HCL Notes
Classifications
T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 26, 2020CVE 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?

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

  1. Affected versionversion=All versions of HCL Notes v10
  2. Affected versionversion=All versions of HCL Notes v11
  3. Affected versionversion=All versions of HCL Notes v9

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

HCL Software · HCL Notesversion=All versions of HCL Notes v10; version=All versions of HCL Notes v11; version=All versions of HCL Notes v9

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
4.3NIST NVDAV:N/AC:M/Au:N/C:P/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

T1204.001User Execution Malicious Link

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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