Vulnerability in 9001 Copyparty
CVE-2026-93353
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 3.1 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (19.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 20th percentile — 19.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
Weakness classification (CWE)
References
- Researcher Disclosure (technical-description, exploit)
- www.vulncheck.com/advisories/copyparty-sftp-volume-restriction-bypass-via-mkdir… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-93353?
- CVE-2026-93353 is a low-severity vulnerability in 9001 Copyparty, classified under Improper Link Resolution Before File Access. CVSS score: 3.1/10. Published 2026-09-24.
- How severe is CVE-2026-93353?
- Low severity. CVSS v3 base score is 3.1 out of 10.