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.
PUBLISHED5.2CWE-59x_open-source
copyparty SFTP Volume Restriction Bypass via mkdir/rmdir/chattr Handlers
Problem type
Affected products
9001
copyparty
<= 1.20.24 - AFFECTED
References
Researcher Disclosure
https://euriconicacio.github.io/blog/cve-2026-93353-a-volume-guard-enforced-one-call-site-at-a-time/
vulncheck.com
https://www.vulncheck.com/advisories/copyparty-sftp-volume-restriction-bypass-via-mkdir-rmdir-chattr-handlers
GitHub Security Advisories
GHSA-3465-46r4-pj75
copyparty contains a volume restriction bypass vulnerability in its SFTP front end that allows...
https://github.com/advisories/GHSA-3465-46r4-pj75copyparty 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.
nvd.nist.gov
https://nvd.nist.gov/vuln/detail/CVE-2026-93353
euriconicacio.github.io
https://euriconicacio.github.io/blog/cve-2026-93353-a-volume-guard-enforced-one-call-site-at-a-time
vulncheck.com
https://www.vulncheck.com/advisories/copyparty-sftp-volume-restriction-bypass-via-mkdir-rmdir-chattr-handlers
github.com
https://github.com/advisories/GHSA-3465-46r4-pj75
JSON source
https://cveawg.mitre.org/api/cve/CVE-2026-93353Click to expand
{
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"cveMetadata": {
"cveId": "CVE-2026-93353",
"assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
"assignerShortName": "VulnCheck",
"dateUpdated": "2026-09-24T20:29:48.722Z",
"dateReserved": "2026-09-17T18:41:40.757Z",
"datePublished": "2026-09-24T20:29:36.253Z",
"state": "PUBLISHED"
},
"containers": {
"cna": {
"providerMetadata": {
"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
"shortName": "VulnCheck",
"dateUpdated": "2026-09-24T20:29:48.722Z"
},
"datePublic": "2026-09-24T00:00:00.000Z",
"title": "copyparty SFTP Volume Restriction Bypass via mkdir/rmdir/chattr Handlers",
"descriptions": [
{
"lang": "en",
"value": "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."
}
],
"affected": [
{
"vendor": "9001",
"product": "copyparty",
"collectionURL": "https://pypi.org/project/copyparty/",
"repo": "https://github.com/9001/copyparty",
"defaultStatus": "unknown",
"versions": [
{
"version": "0",
"status": "affected",
"versionType": "semver",
"lessThanOrEqual": "1.20.24"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"lang": "en",
"description": "Improper Link Resolution Before File Access ('Link Following')",
"cweId": "CWE-59",
"type": "CWE"
},
{
"lang": "en",
"description": "Improper Protection of Alternate Path",
"cweId": "CWE-424",
"type": "CWE"
}
]
}
],
"references": [
{
"url": "https://euriconicacio.github.io/blog/cve-2026-93353-a-volume-guard-enforced-one-call-site-at-a-time/",
"name": "Researcher Disclosure",
"tags": [
"technical-description",
"exploit"
]
},
{
"url": "https://www.vulncheck.com/advisories/copyparty-sftp-volume-restriction-bypass-via-mkdir-rmdir-chattr-handlers",
"tags": [
"third-party-advisory"
]
}
],
"metrics": [
{
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
},
{
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
],
"cvssV3_1": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N",
"attackVector": "NETWORK",
"attackComplexity": "HIGH",
"privilegesRequired": "LOW",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "NONE",
"integrityImpact": "HIGH",
"availabilityImpact": "NONE",
"baseScore": 5.3,
"baseSeverity": "MEDIUM"
}
}
],
"credits": [
{
"lang": "en",
"value": "euriconicacio",
"type": "finder"
}
],
"tags": [
"x_open-source"
]
}
}
}