CVE-2019-3977

Name: CVE-2019-3977
Creator: NVD / NIST
Published: 2019-10-29T19:15:20.407+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 1.06%

Last modified Jun 17, 2026

CVE-2019-3977 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. RouterOS 6.45.6 Stable, RouterOS 6.44.5 Long-term, and below insufficiently validate where upgrade packages are download from when using the autoupgrade feature. Therefore, a remote attacker can trick the router into "upgrading" to an older version of RouterOS and possibly reseting all the system's usernames and passwords.. EPSS estimates a 1.06% chance of exploitation in the next 30 days.

Description

RouterOS 6.45.6 Stable, RouterOS 6.44.5 Long-term, and below insufficiently validate where upgrade packages are download from when using the autoupgrade feature. Therefore, a remote attacker can trick the router into "upgrading" to an older version of RouterOS and possibly reseting all the system's usernames and passwords.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS Probability

1.06%

60.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Mikrotik	Routeros	<= 6.44.5
Mikrotik	Routeros	<= 6.45.6

References

https://www.tenable.com/security/research/tra-2019-46Third Party Advisory
https://www.tenable.com/security/research/tra-2019-46Third Party Advisory

Timeline

Published: Oct 29, 2019
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2019-3977?

How severe is CVE-2019-3977?

CVE-2019-3977 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 1.06% probability of exploitation in the next 30 days.

How do I fix CVE-2019-3977?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2019-3977?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST