# CVE-2021-47818: DupTerminator 1.4.5639.37199 - Denial of Service

> Attackers can crash the DupTerminator desktop application by inputting a long character string into the Excluded text box.

- **Severity:** Medium 4.6 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 16 Jan 2026
- **Updated:** 2 Feb 2026
- **Also known as:** GHSA-2cx4-58j3-2jr5

## What is CVE-2021-47818?

CVE-2021-47818 is a medium-severity denial of service vulnerability in DupTerminator, published on 16 Jan 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

DupTerminator 1.4.5639.37199 contains a denial of service vulnerability that allows attackers to crash the application by inputting a long character string in the Excluded text box. Attackers can generate a payload of 8000 repeated characters to trigger the application to stop working on Windows 10.

Weakness: CWE-1284 (Improper Validation of Specified Quantity in Input)

## Which versions are affected by CVE-2021-47818?


## How do I fix CVE-2021-47818?

No fix has been published for CVE-2021-47818 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-47818 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-47818 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-47818 and fix it if it is affected.

What it is: CVE-2021-47818 is a medium-severity denial of service vulnerability in DupTerminator, published on 16 Jan 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-47818 exists.

Affected product: DupTerminator. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2021-47818/ (Markdown: https://insights.sbomify.com/CVE-2021-47818/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-47818
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-47818
- OSV: https://osv.dev/vulnerability/CVE-2021-47818

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-47818/
Summaries are generated and may contain mistakes; the official description above is the record.