CVE-2026-53433

Denial of Service in fzf

CVSS 5.7 MEDIUMEPSS 0.1%CWE-407

Vexday Risk Score

13Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS 5.7EPSS 0.1%KEV nãoPoC —Nuclei —Metasploit —Patch —

Lifecycle

30 Jun 2026Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

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:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Affected products

fzf · fzf

References

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