# CVE-2026-53433: Denial of Service in fzf


- **Severity:** Medium 5.7 (`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`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 30 Jun 2026
- **Updated:** 30 Jun 2026
- **Also known as:** DEBIAN-CVE-2026-53433, GHSA-mvmf-94v6-879g, GO-2026-6620, UBUNTU-CVE-2026-53433

## What is CVE-2026-53433?

CVE-2026-53433 is a medium-severity vulnerability in fzf, published on 30 Jun 2026. 

### 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.

Weakness: CWE-407 (Inefficient Algorithmic Complexity)

## Which versions are affected by CVE-2026-53433?

3 open source packages ship an affected version, including github.com/junegunn/fzf. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/junegunn/fzf` | Go | All versions | 0.73.1 |
| `github.com/junegunn/fzf` | Go | All versions | 0.73.1 |
| `github.com/junegunn/fzf` | Go | All versions | 0.73.1 |

Products: Junegunn Fzf.

## How do I fix CVE-2026-53433?

Upgrade github.com/junegunn/fzf to 0.73.1 or later.

## Is CVE-2026-53433 being exploited?

There is no known exploitation of CVE-2026-53433 in the wild and no public exploit code.

## Other vulnerabilities in fzf

- [CVE-2026-53432](https://insights.sbomify.com/CVE-2026-53432/): Integer Overflow in fzf (medium 5.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53433 and fix it if it is affected.

What it is: CVE-2026-53433 is a medium-severity vulnerability in fzf, published on 30 Jun 2026. 
Exploitation: There is no known exploitation of CVE-2026-53433 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/junegunn/fzf (Go): affected all versions; fixed in 0.73.1
- github.com/junegunn/fzf (Go): affected all versions; fixed in 0.73.1
- github.com/junegunn/fzf (Go): affected all versions; fixed in 0.73.1

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-53433/ (Markdown: https://insights.sbomify.com/CVE-2026-53433/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53433
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53433
- OSV: https://osv.dev/vulnerability/CVE-2026-53433

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53433/
Summaries are generated and may contain mistakes; the official description above is the record.