CVE-2026-53433: fzf vulnerable to denial of service through quadratic HTTP request-body accumulation

June 30, 2026 (updated September 30, 2026)

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.

References

Code Behaviors & Features

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