CVE-2019-18684
sudo: privilege escalation via write access to file descriptor 3 of the sudo process
Severity
ModerateRed Hat Product Security
CVSS 3.0
Review impact separately from score.
Published · November 7, 2019
Updated · November 22, 2025
Description
Sudo through 1.8.29 allows local users to escalate to root if they have write access to file descriptor 3 of the sudo process. This occurs because of a race condition between determining a uid, and the setresuid and openat system calls. The attacker can write "ALL ALL=(ALL) NOPASSWD:ALL" to /proc/#####/fd/3 at a time when Sudo is prompting for a password. NOTE: This has been disputed due to the way Linux /proc works. It has been argued that writing to /proc/#####/fd/3 would only be viable if you had permission to write to /etc/sudoers. Even with write permission to /proc/#####/fd/3, it would not help you write to /etc/sudoers
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 3.0 · 6.7CVSS:3.0/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H
CWE-362 · Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')