CVE-2019-3977 Supply chain in MikroTik RouterOS
Attackers can trick RouterOS into installing malicious or older firmware via autoupgrade, potentially resetting credentials and bypassing security controls.
- 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-2019-3977?
CVE-2019-3977 is a high-severity vulnerability in Mikrotik Routeros, published on 28 Oct 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-494
Which versions are affected by CVE-2019-3977?
It affects 1 product.
Products include Mikrotik Routeros.
How do I fix CVE-2019-3977?
No fix has been published for CVE-2019-3977 yet. Limit exposure of the affected software until one is available.
Is CVE-2019-3977 being exploited?
There is no known exploitation of CVE-2019-3977 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-94gr-5fp3-387v.