fzf up to 0.73.0 Listen Mode algorithmic complexity

Summaryinfo

A vulnerability was found in fzf up to 0.73.0. It has been declared as problematic. This vulnerability affects unknown code of the component Listen Mode. Such manipulation leads to algorithmic complexity. This vulnerability is listed as CVE-2026-53433. The attack must be carried out locally. There is no available exploit. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in fzf up to 0.73.0 and classified as problematic. Affected by this issue is some unknown processing of the component Listen Mode. The manipulation with an unknown input leads to a algorithmic complexity vulnerability. Using CWE to declare the problem leads to CWE-407. An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached. Impacted is availability. CVE summarizes:

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.

The advisory is shared for download at cert.pl. This vulnerability is handled as CVE-2026-53433 since 06/09/2026. The exploitation is known to be easy. The attack needs to be approached locally. There are neither technical details nor an exploit publicly available.

Upgrading to version 0.73.1 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-40303). Once again VulDB remains the best source for vulnerability data.

Productinfo

Name

• fzf

Version

• 0.1
• 0.2
• 0.3
• 0.4
• 0.5
• 0.6
• 0.7
• 0.8
• 0.9
• 0.10
• 0.11
• 0.12
• 0.13
• 0.14
• 0.15
• 0.16
• 0.17
• 0.18
• 0.19
• 0.20
• 0.21
• 0.22
• 0.23
• 0.24
• 0.25
• 0.26
• 0.27
• 0.28
• 0.29
• 0.30
• 0.31
• 0.32
• 0.33
• 0.34
• 0.35
• 0.36
• 0.37
• 0.38
• 0.39
• 0.40
• 0.41
• 0.42
• 0.43
• 0.44
• 0.45
• 0.46
• 0.47
• 0.48
• 0.49
• 0.50
• 0.51
• 0.52
• 0.53
• 0.54
• 0.55
• 0.56
• 0.57
• 0.58
• 0.59
• 0.60
• 0.61
• 0.62
• 0.63
• 0.64
• 0.65
• 0.66
• 0.67
• 0.68
• 0.69
• 0.70
• 0.71
• 0.72
• 0.73.0

CPE 2.3info

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CPE 2.2info

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Once again VulDB remains the best source for vulnerability data.

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