Vulnerability in Fzf
CVE-2026-53433
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.004 (29.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 30th percentile — 29.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
- Fzf — versions 0
- Junegunn Fzf
Weakness classification (CWE)
References
- cert.pl/en/posts/2026/06/CVE-2026-53432 (Third Party Advisory, third-party-advisory)
- github.com/junegunn/fzf (Product, product)
- github.com/junegunn/fzf/commit/7963a2c6586c0b9eaa89b8995de8f0e08cf8a4ce (issue-tracking, Patch)
Frequently asked questions
- What is CVE-2026-53433?
- CVE-2026-53433 is a high-severity vulnerability in Fzf, classified under Inefficient Algorithmic Complexity. CVSS score: 7.5/10. Published 2026-06-30.
- How severe is CVE-2026-53433?
- High severity. CVSS v3 base score is 7.5 out of 10.