Medium
Denial of Service in fzf
Type: advisorySources: OSV
fzf is vulnerable to a Denial of Service (DoS) due to inefficient HTTP body processing in the --listen mode due to inefficient HTTP body processing using repeated string concatenation, resulting in quadratic time complexity (O(n²)). A crafted POST request with many small segments can trigger excessive CPU usage during request handling.This allows a single malicious request to monopolize the single‑threaded HTTP server, blocking all other clients and resulting in denial of service. This issue was fixed in version 0.73.1.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-53433
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 3 Nov 2026, 07:10 UTC · Revision 1
Source evidence
fzf is vulnerable to a Denial of Service (DoS) due to inefficient HTTP body processing in the --listen mode due to inefficient HTTP body processing using repeated string concatenation, resulting in quadratic time complexity (O(n²)). A crafted POST request with many small segments can trigger excessive CPU usage during request handling.This allows a single malicious request to monopolize the single‑threaded HTTP server, blocking all other clients and resulting in denial of service. This issue was fixed in version 0.73.1.
osv:CVE-2026-53433
Complete source record
{
"id": "5dc16e421c3a78d73a380b26c2017378238b9972cd244b540a1c2fc8ceabd4c7",
"url": "https://osv.dev/vulnerability/CVE-2026-53433",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "Denial of Service in fzf",
"summary": "fzf is vulnerable to a Denial of Service (DoS) due to inefficient HTTP body processing in the --listen mode due to inefficient HTTP body processing using repeated string concatenation, resulting in quadratic time complexity (O(n²)). A crafted POST request with many small segments can trigger excessive CPU usage during request handling.This allows a single malicious request to monopolize the single‑threaded HTTP server, blocking all other clients and resulting in denial of service. This issue was fixed in version 0.73.1.",
"evidence": "osv:CVE-2026-53433",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2026-53433",
"aliases": [
"CVE-2026-53433",
"GHSA-mvmf-94v6-879g",
"GO-2026-6620"
],
"metrics": [
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/junegunn/fzf",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"fixed": "ce4bef75954bebd87e0886435bcf8c6904328ab0"
},
{
"fixed": "7963a2c6586c0b9eaa89b8995de8f0e08cf8a4ce"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:junegunn:fzf:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "0"
},
{
"fixed": "0.73.1"
}
],
"source": "CPE_RANGE"
},
{
"range": [
{
"fixed": "7963a2c6586c0b9eaa89b8995de8f0e08cf8a4ce"
}
],
"source": "REFERENCES_COMMIT"
}
]
}
}
],
"versions": [
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],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53433.json"
}
}
],
"modified": "2026-10-28T02:30:26.657695500Z",
"provider": "osv",
"references": [
"https://cert.pl/en/posts/2026/06/CVE-2026-53432",
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53433.json",
"https://nvd.nist.gov/vuln/detail/CVE-2026-53433",
"https://github.com/junegunn/fzf/commit/7963a2c6586c0b9eaa89b8995de8f0e08cf8a4ce",
"https://github.com/junegunn/fzf"
],
"provider_metadata": {
"cwe_ids": [
"CWE-407"
],
"cna_assigner": "CERT-PL",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53433.json"
}
},
"related_cves": [
{
"value": "CVE-2026-53433",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 493266,
"published_at": "2026-06-30T12:01:14.407+00:00"
}