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Vulnerability record · CVE-2019-18684 · published 4 November 2019

CVE-2019-18684: Sudo project sudo race condition vulnerability

Sudo Project · Sudo

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

7.0 CVSS 3.1 High EPSS 0.29% · top 77.8% CWE-362 · Race condition
7.0CVSS 3.1 base score, v2 6.9
0.29%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References, 2 tagged exploit
17 Jun 2026Last modified by NVD

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:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://gist.github.com/oxagast/51171aa161074188a11d96cbef884bbd ExploitThird Party Advisory
https://gist.github.com/oxagast/51171aa161074188a11d96cbef884bbd ExploitThird Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2019-18684), CISA KEV, FIRST EPSS (scores of 2026-11-13). This page is refreshed as NVD updates the record.