CVE-2026-39042 Integer overflow in n/a
A remote attacker can cause a denial of service in MikroTik RouterOS via an integer overflow in the unflatten function.
- 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-2026-39042?
CVE-2026-39042 is a high-severity vulnerability in n/a, published on 13 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
An issue in MikroTIk (SIA Mikrotikls, Latvia) RouterOS 7.21.x before v.7.21.4 and 7.22.x before v.7.22.2 allows a remote attacker to cause a denial of service via the unflatten() function in libumsg.so.
Weakness: CWE-190
Which versions are affected by CVE-2026-39042?
How do I fix CVE-2026-39042?
No fix has been published for CVE-2026-39042 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-39042 being exploited?
There is no known exploitation of CVE-2026-39042 in the wild and no public exploit code.
Sources
Also known as GHSA-p5h9-77xr-72r8.