What’s Vulnerable › Vulnerabilities

CVE-2026-53433: Denial of Service in fzf

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-30 · updated 2026-07-02
• Weakness: CWE-407

Description

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.

Affected products

• fzf: before 0.73.1 — fixed in 0.73.1

How to fix

Upgrade to a fixed version: fzf 0.73.1. Check the vendor advisory for mitigations.

References

• https://cert.pl/en/posts/2026/06/CVE-2026-53432
• https://github.com/junegunn/fzf
• https://github.com/junegunn/fzf/commit/7963a2c6586c0b9eaa89b8995de8f0e08cf8a4ce

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