Sudo: vulnerability flaw under attack

What is affected

Sudo is mostly run by companies, schools and public bodies, not on home computers. You are unlikely to have it yourself, but organisations that hold your data may. Breaches that start with flaws like this one are how personal data ends up leaked.

Sudo contains an inclusion of functionality from untrusted control sphere vulnerability. This vulnerability could allow local attacker to leverage sudo’s -R (--chroot) option to run arbitrary commands as root, even if they are not listed in the sudoers file.

What an attacker can do

This is a vulnerability flaw. It lets an attacker misuse the product in a way its maker did not intend. CISA lists it because attackers are confirmed to be using it against real systems.

How it is reached

Needs access to the device or a file opened on it

Access the attacker needs

A basic user account

Does the victim have to do something?

No, works without the victim doing anything

What to do

1. At home: nothing to install. Keep your own devices updated and use a different password for every service, so that a breach at one organisation does not open your other accounts.
2. If you administer Sudo at work: apply the vendor's fix or mitigation now and review logs for signs of compromise, because the flaw was being exploited before it was listed.
3. If the product is past its support date and no fix exists, take it off the internet or retire it.

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Vendor advisories and fixes

• sudo.wswww.sudo.ws/security/advisories/chroot_bug/

How urgent is it

CISA added this vulnerability to its Known Exploited Vulnerabilities catalogue on September 29, 2025, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by October 20, 2025, a deadline that has already passed. That deadline does not bind anyone else, but it shows how seriously the agency rates it.

The EPSS model estimates a 55% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 99.0% of all scored vulnerabilities.

Its CVSS severity score is 7.8 out of 10 (high), as recorded in the US National Vulnerability Database.

Technical description

Sudo before 1.9.17p1 allows local users to obtain root access because /etc/nsswitch.conf from a user-controlled directory is used with the --chroot option.