CVE-2019-3981Public exploitNetwork attack vector

Credential disclosure via authentication protocol downgrade

Published Jan 14, 2020 · Updated Aug 4, 2024

Authentication downgrade in MikroTik WinBox 3.20 and earlier allows man-in-the-middle attackers to recover a username and password hash. The client falls back from ECSRP-5 to legacy Diffie-Hellman when an intermediary ignores its first negotiation message, then sends the username and an MD5 password hash salted with an attacker-chosen value. The attacker must intercept a legitimate RouterOS login on the network path; the disclosed consequence is credential-material exposure, not configuration change or service interruption.

CVSS severity3.7
Low
EPSS probability1.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication downgrade in MikroTik WinBox 3.20 and earlier allows man-in-the-middle attackers to recover a username and password hash. The client falls back from ECSRP-5 to legacy Diffie-Hellman when an intermediary ignores its first negotiation message, then sends the username and an MD5 password hash salted with an attacker-chosen value. The attacker must intercept a legitimate RouterOS login on the network path; the disclosed consequence is credential-material exposure, not configuration change or service interruption.

The record

CVE
CVE-2019-3981
Published
Jan 14, 2020
Updated
Aug 4, 2024
Vendor
MikroTik
Product
WinBox
Classifications
CWE-300, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 14, 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=Winbox 3.20 and below.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

MikroTik · WinBoxversion=Winbox 3.20 and below.

Published CVSS scores

4.3TenableAV:N/AC:M/Au:N/C:P/I:N/A:N
3.7NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/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 exploitPublished

Weakness, pattern, technique

CWE-300Channel Accessible by Non-Endpoint
T1557Adversary-in-the-Middle

Public exploit references

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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