CVE-2026-53433

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.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://cert.pl/en/posts/2026/06/CVE-2026-53432	Third Party Advisory
https://github.com/junegunn/fzf	Product
https://github.com/junegunn/fzf/commit/7963a2c6586c0b9eaa89b8995de8f0e08cf8a4ce	Patch

Configurations

Configuration 1 (hide)

cpe:2.3:a:junegunn:fzf:*:*:*:*:*:*:*:*

History

02 Jul 2026, 19:01

Type	Values Removed	Values Added
First Time		Junegunn Junegunn fzf
CPE		cpe:2.3:a:junegunn:fzf::::::::
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 7.5
References	~~() https://cert.pl/en/posts/2026/06/CVE-2026-53432 -~~	() https://cert.pl/en/posts/2026/06/CVE-2026-53432 - Third Party Advisory
References	~~() https://github.com/junegunn/fzf -~~	() https://github.com/junegunn/fzf - Product
References	~~() https://github.com/junegunn/fzf/commit/7963a2c6586c0b9eaa89b8995de8f0e08cf8a4ce -~~	() https://github.com/junegunn/fzf/commit/7963a2c6586c0b9eaa89b8995de8f0e08cf8a4ce - Patch

30 Jun 2026, 13:19

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-06-30 13:19

Updated : 2026-07-02 19:01

NVD link : CVE-2026-53433

Mitre link : CVE-2026-53433

CVE.ORG link : CVE-2026-53433

JSON object : View

Products Affected

junegunn

fzf

CWE

CWE-407

Inefficient Algorithmic Complexity

{"id": "CVE-2026-53433", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-53433", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-06-30T13:32:32.210950Z"}}], "cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 3.9}], "cvssMetricV40": [{"type": "Secondary", "source": "cvd@cert.pl", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 5.7, "Automatable": "NOT_DEFINED", "attackVector": "LOCAL", "baseSeverity": "MEDIUM", "valueDensity": "NOT_DEFINED", "vectorString": "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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "LOW", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "NONE", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "confidentialityRequirement": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED"}}]}, "affected": [{"source": "cvd@cert.pl", "affectedData": [{"repo": "https://github.com/junegunn/fzf", "vendor": "fzf", "product": "fzf", "versions": [{"status": "affected", "version": "0", "lessThan": "0.73.1", "versionType": "semver"}], "programFiles": ["src/server.go"], "defaultStatus": "unaffected"}]}], "published": "2026-06-30T13:19:13.407", "references": [{"url": "https://cert.pl/en/posts/2026/06/CVE-2026-53432", "tags": ["Third Party Advisory"], "source": "cvd@cert.pl"}, {"url": "https://github.com/junegunn/fzf", "tags": ["Product"], "source": "cvd@cert.pl"}, {"url": "https://github.com/junegunn/fzf/commit/7963a2c6586c0b9eaa89b8995de8f0e08cf8a4ce", "tags": ["Patch"], "source": "cvd@cert.pl"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "cvd@cert.pl", "description": [{"lang": "en", "value": "CWE-407"}]}], "descriptions": [{"lang": "en", "value": "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(n\u00b2)). 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\u2011threaded HTTP server, blocking all other clients and resulting in denial of service.\n\nThis issue was fixed in version 0.73.1."}], "lastModified": "2026-07-02T19:01:45.227", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:junegunn:fzf:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "1B9C3708-1223-421E-9641-DABD4A023A81", "versionEndExcluding": "0.73.1"}], "operator": "OR"}]}], "sourceIdentifier": "cvd@cert.pl"}