sudo-rs Session File Relative Path Traversal vulnerability

Summary

CVE	CVE-2023-42456
State	PUBLISHED
Assigner	GitHub_M
Source Priority	CVE Program / NVD first with legacy fallback
Published	2023-09-21 16:15:09 UTC
Updated	2026-06-10 15:16:29 UTC
Description	Sudo-rs, a memory safe implementation of sudo and su, allows users to not have to enter authentication at every sudo attempt, but instead only requiring authentication every once in a while in every terminal or process group. Only once a configurable timeout has passed will the user have to re-authenticate themselves. Supporting this functionality is a set of session files (timestamps) for each user, stored in `/var/run/sudo-rs/ts`. These files are named according to the username from which the sudo attempt is made (the origin user). An issue was discovered in versions prior to 0.2.1 where usernames containing the `.` and `/` characters could result in the corruption of specific files on the filesystem. As usernames are generally not limited by the characters they can contain, a username appearing to be a relative path can be constructed. For example we could add a user to the system containing the username `../../../../bin/cp`. When logged in as a user with that name, that user could run `sudo -K` to clear their session record file. The session code then constructs the path to the session file by concatenating the username to the session file storage directory, resulting in a resolved path of `/bin/cp`. The code then clears that file, resulting in the `cp` binary effectively being removed from the system. An attacker needs to be able to login as a user with a constructed username. Given that such a username is unlikely to exist on an existing system, they will also need to be able to create the users with the constructed usernames. The issue is patched in version 0.2.1 of sudo-rs. Sudo-rs now uses the uid for the user instead of their username for determining the filename. Note that an upgrade to this version will result in existing session files being ignored and users will be forced to re-authenticate. It also fully eliminates any possibility of path traversal, given that uids are always integer values. The `sudo -K` and `sudo -k` commands can run, even if a user has no sudo access. As a workaround, make sure that one's system does not contain any users with a specially crafted username. While this is the case and while untrusted users do not have the ability to create arbitrary users on the system, one should not be able to exploit this issue.

Risk And Classification

Primary CVSS: v3.1 8.1 HIGH from [email protected]

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

EPSS: 0.005710000 probability, percentile 0.425660000 (date 2026-06-16)

Problem Types: CWE-22 | CWE-23 | CWE-23 CWE-23: Relative Path Traversal | CWE-22 CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Version	Source	Type	Score	Severity	Vector
3.1	[email protected]	Primary	8.1	HIGH	`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H`
3.1	[email protected]	Secondary	3.3	LOW	`CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:L`
3.1	CNA	DECLARED	3.3	LOW	`CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:L`

CVSS v3.1 Breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

High

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

NVD Known Affected Configurations (CPE 2.3)

Type	Vendor	Product	Version	Update	Edition	Language
Application	Memorysafety	Sudo	All	All	All	All

Vendor Declared Affected Products

Source	Vendor	Product	Version	Platforms
CNA	Memorysafety	Sudo-rs	affected < 0.2.1	Not specified

References

Reference	Source	Link	Tags
Session File Relative Path Traversal in sudo-rs · Advisory · memorysafety/sudo-rs · GitHub	af854a3a-2127-422b-91ae-364da2661108	github.com	Vendor Advisory
Merge pull request from GHSA-2r3c-m6v7-9354 · memorysafety/sudo-rs@bfdbda2 · GitHub	af854a3a-2127-422b-91ae-364da2661108	github.com	Patch
oss-security - Session File Relative Path Traversal in sudo-rs	af854a3a-2127-422b-91ae-364da2661108	www.openwall.com
github.com/trifectatechfoundation/sudo-rs/security/advisories/GHSA-2r3c-...	[email protected]	github.com
sudo-rs' first security audit - Ferrous Systems	af854a3a-2127-422b-91ae-364da2661108	ferrous-systems.com
CVE Program record	CVE.ORG	www.cve.org	canonical
NVD vulnerability detail	NVD	nvd.nist.gov	canonical, analysis

No vendor comments have been submitted for this CVE.

Legacy QID Mappings

995368 Rust (Rust) Security Update for sudo-rs (GHSA-2r3c-m6v7-9354)