Vulnerability · Published Jun 30, 2026 · Assigned by CERT-PL
CVE-2026-53433Denial of Service in fzf
Medium 5.7
In plain English
A medium-severity security flaw in fzf from fzf. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 32% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | fzf | no fix listed | DEBIAN-CVE-2026-53433 |
| Debian:13 | fzf | no fix listed | DEBIAN-CVE-2026-53433 |
| Debian:14 | fzf | 0.73.1-1 | DEBIAN-CVE-2026-53433 |
| Go | github.com/junegunn/fzf | 0.73.1 | GHSA-mvmf-94v6-879g |
| Go | github.com/junegunn/fzf | 0.73.1 | GO-2026-6620 |
| Ubuntu:22.04:LTS | fzf | no fix listed | UBUNTU-CVE-2026-53433 |
| Ubuntu:24.04:LTS | fzf | no fix listed | UBUNTU-CVE-2026-53433 |
| Ubuntu:25.10 | fzf | no fix listed | UBUNTU-CVE-2026-53433 |
| Ubuntu:26.04:LTS | fzf | no fix listed | UBUNTU-CVE-2026-53433 |
Affected products (as reported)
Weakness: CWE-407 · Vector: 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
References
- https://cert.pl/en/posts/2026/06/CVE-2026-53432 third-party-advisory
- https://github.com/junegunn/fzf product
- https://github.com/junegunn/fzf/commit/7963a2c6586c0b9eaa89b8995de8f0e08cf8a4ce issue-tracking