basic-ftp: Quadratic-time CPU denial of service in Client.list() Unix directory-listing parser (RE_LINE backtracking)
basic-ftp is an FTP client for Node.js. Prior to 6.2.1, Client.list() can be forced by a malicious or compromised FTP server to spend quadratic CPU time parsing a directory listing because the RE_LINE expression in src/parseListUnix.ts backtracks across adjacent variable-length owner and group fields when a long Unix-style line has a valid prefix but cannot satisfy the later size and date fields. parseList() selects a parser from the last nonblank line and then applies it to every line, so a normal final line can select the Unix parser while an earlier crafted line blocks the Node.js event loop and freezes the process. This issue is fixed in version 6.2.1.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-102990
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 7 Nov 2026, 03:55 UTC · Revision 1
Source evidence
basic-ftp: Quadratic-time CPU denial of service in Client.list() Unix directory-listing parser (RE_LINE backtracking)
core-osv · Original sourcePublished 30 Sept 2026, 19:44 UTC
basic-ftp is an FTP client for Node.js. Prior to 6.2.1, Client.list() can be forced by a malicious or compromised FTP server to spend quadratic CPU time parsing a directory listing because the RE_LINE expression in src/parseListUnix.ts backtracks across adjacent variable-length owner and group fields when a long Unix-style line has a valid prefix but cannot satisfy the later size and date fields. parseList() selects a parser from the last nonblank line and then applies it to every line, so a normal final line can select the Unix parser while an earlier crafted line blocks the Node.js event loop and freezes the process. This issue is fixed in version 6.2.1.
osv:CVE-2026-102990
Complete source record
{
"id": "a6d038752f83eece17cac59ca60b49a9b1b758ed4a25a77852321e3888642ed3",
"url": "https://osv.dev/vulnerability/CVE-2026-102990",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "basic-ftp: Quadratic-time CPU denial of service in Client.list() Unix directory-listing parser (RE_LINE backtracking)",
"summary": "basic-ftp is an FTP client for Node.js. Prior to 6.2.1, Client.list() can be forced by a malicious or compromised FTP server to spend quadratic CPU time parsing a directory listing because the RE_LINE expression in src/parseListUnix.ts backtracks across adjacent variable-length owner and group fields when a long Unix-style line has a valid prefix but cannot satisfy the later size and date fields. parseList() selects a parser from the last nonblank line and then applies it to every line, so a normal final line can select the Unix parser while an earlier crafted line blocks the Node.js event loop and freezes the process. This issue is fixed in version 6.2.1.",
"evidence": "osv:CVE-2026-102990",
"products": [],
"severity": "high",
"structured": {
"id": "CVE-2026-102990",
"aliases": [
"CVE-2026-102990",
"GHSA-c475-qrg2-pj4r"
],
"metrics": [
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/patrickjuchli/basic-ftp",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"fixed": "a5b160ff7d127130107789029aec98632c51fd60"
},
{
"fixed": "d0d9e07c56e519587bb50532ac6eadbb0cb0cfe9"
}
],
"database_specific": {
"extracted_events": [
{
"range": [
{
"introduced": "0"
},
{
"fixed": "6.2.1"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StringRangeExpression"
},
{
"range": [
{
"fixed": "d0d9e07c56e519587bb50532ac6eadbb0cb0cfe9"
}
],
"source": "REFERENCES_COMMIT"
},
{
"range": [
{
"fixed": "a5b160ff7d127130107789029aec98632c51fd60"
}
],
"source": "REFERENCES_TAG",
"original_tag": "v6.2.1"
}
]
}
}
],
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"1.0.6",
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],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-102990.json"
}
}
],
"modified": "2026-10-28T02:30:49.751723152Z",
"provider": "osv",
"references": [
"https://github.com/patrickjuchli/basic-ftp/releases/tag/v6.2.1",
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/102xxx/CVE-2026-102990.json",
"https://github.com/patrickjuchli/basic-ftp/security/advisories/GHSA-c475-qrg2-pj4r",
"https://nvd.nist.gov/vuln/detail/CVE-2026-102990",
"https://github.com/patrickjuchli/basic-ftp/commit/d0d9e07c56e519587bb50532ac6eadbb0cb0cfe9"
],
"provider_metadata": {
"cwe_ids": [
"CWE-1333"
],
"cna_assigner": "GitHub_M",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/102xxx/CVE-2026-102990.json"
}
},
"related_cves": [
{
"value": "CVE-2026-102990",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 517925,
"published_at": "2026-09-30T19:44:47.303+00:00"
}