CVE-2019-3981 Weak cryptography in WinBox
Man-in-the-middle attackers can downgrade authentication to recover user credentials, requiring users to upgrade the Winbox client.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2019-3981?
CVE-2019-3981 is a low-severity vulnerability in Mikrotik Routeros, published on 14 Jan 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
MikroTik Winbox 3.20 and below is vulnerable to man in the middle attacks. A man in the middle can downgrade the client's authentication protocol and recover the user's username and MD5 hashed password.
Weakness: CWE-300
Which versions are affected by CVE-2019-3981?
It affects 2 products.
Products include Mikrotik Routeros, Mikrotik Winbox.
How do I fix CVE-2019-3981?
No fix has been published for CVE-2019-3981 yet. Limit exposure of the affected software until one is available.
Is CVE-2019-3981 being exploited?
There is no known exploitation of CVE-2019-3981 in the wild and no public exploit code.
Other vulnerabilities in Mikrotik Routeros
- CVE-2018-7445 MikroTik RouterOS Stack-Based Buffer Overflow
- CVE-2026-86060 MikroTik RouterOS Improper Neutralization of Argument Delimiters in a Command
- CVE-2018-14847 MikroTik Router OS Directory Traversal
- CVE-2026-67277 MikroTik RouterOS Missing Authentication for Critical Function
- CVE-2026-67279 Mikrotik RouterOS Improper Enforcement of Behavioral Workflow
Sources
Also known as GHSA-pg5r-4rf5-r7hv.