CVE-2020-27720 Denial of service in BIG-IP LTM/CGNAT
An attacker can cause a denial of service by sending specific traffic to BIG-IP LTM/CGNAT devices configured with non-default NAT66 settings.
- 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-2020-27720?
CVE-2020-27720 is a high-severity denial of service vulnerability in F5 Big-Ip Carrier-Grade Nat, published on 24 Dec 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
On BIG-IP LTM/CGNAT version 16.0.0-16.0.0.1, 15.1.0-15.1.0.5, 14.1.0-14.1.3, and 13.1.0-13.1.3.5, when processing NAT66 traffic with Port Block Allocation (PBA) mode and SP-DAG enabled, and dag-ipv6-prefix-len configured with a value less than the default of 128, an undisclosed traffic pattern may cause the Traffic Management Microkernel (TMM) to restart.
Which versions are affected by CVE-2020-27720?
It affects 2 products.
Products include F5 Big-Ip Carrier-Grade Nat, F5 Big-Ip Local Traffic Manager.
How do I fix CVE-2020-27720?
No fix has been published for CVE-2020-27720 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2020-27720 being exploited?
There is no known exploitation of CVE-2020-27720 in the wild and no public exploit code.
Sources
Also known as GHSA-hp39-4vrr-9cjg.