CVE-2026-93353

low

Description

copyparty contains a volume restriction bypass vulnerability in its SFTP front end that allows authenticated SFTP users to create, remove, and truncate arbitrary paths outside permitted volume boundaries by exploiting three handlers that bypass the xvol volflag enforcement. The _mkdir, _rmdir, and _chattr handlers construct destination paths using vfs.get(), vn.canonical(), and os.path.join() without invoking the chk_ap access check, enabling attackers to traverse symlinks leaving a volume's top directory and perform unauthorized file creation, deletion, or truncation via SSH_FXP_SETSTAT operations on paths outside any volume the account is authorized to access.

References

https://www.vulncheck.com/advisories/copyparty-sftp-volume-restriction-bypass-via-mkdir-rmdir-chattr-handlers

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-86466

https://euriconicacio.github.io/blog/cve-2026-93353-a-volume-guard-enforced-one-call-site-at-a-time/

Details

Source: Mitre, NVD

Published: 2026-09-24

Updated: 2026-09-30

Risk Information

CVSS v2

Base Score: 2.1

Vector: CVSS2#AV:N/AC:H/Au:S/C:N/I:P/A:N

Severity: Low

CVSS v3

Base Score: 3.1

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

Severity: Low

CVSS v4

Base Score: 2.3

Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

Severity: Low

EPSS

EPSS: 0.00323