Bug 2494891 (CVE-2026-53433)

Summary: CVE-2026-53433 fzf: fzf: Denial of Service via inefficient HTTP body processing
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in fzf, a command-line fuzzy finder. This vulnerability allows a remote attacker to cause a Denial of Service (DoS) by sending a crafted POST request with many small segments to the `--listen` mode. The inefficient HTTP body processing, which uses repeated string concatenation, leads to quadratic time complexity, causing excessive CPU usage and blocking other clients.
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Bug Depends On: 2494940, 2494941    
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Description OSIDB Bzimport 2026-06-30 13:09:16 UTC 
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.