CVE-2020-16127 accountsservice .pam_environment infinite loop
An attacker can cause a denial of service by symlinking /dev/zero to ~/.pam_environment, triggering an infinite loop in AccountsService.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2020-16127?
CVE-2020-16127 is a low-severity denial of service vulnerability in Freedesktop accountsservice, published on 11 Nov 2020. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
An Ubuntu-specific modification to AccountsService in versions before 0.6.55-0ubuntu13.2, among other earlier versions, would perform unbounded read operations on user-controlled ~/.pam_environment files, allowing an infinite loop if /dev/zero is symlinked to this location.
Which versions are affected by CVE-2020-16127?
It affects 1 product.
Products include Freedesktop Accountsservice.
How do I fix CVE-2020-16127?
Apply the vendor's patch.
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-2020-16127 being exploited?
There is no known exploitation of CVE-2020-16127 in the wild and no public exploit code.
Other vulnerabilities in Freedesktop accountsservice
Sources
Also known as GHSA-vg2p-x98m-7mxr, UBUNTU-CVE-2020-16127.