# CVE-2021-20687: Cross-site request forgery in Kagemai

> Remote attackers can hijack administrator sessions in Kagemai via CSRF, potentially leading to full account takeover.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 7 Apr 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-jch2-6x9c-524j

## What is CVE-2021-20687?

CVE-2021-20687 is a high-severity vulnerability in daifukuya.com Kagemai, published on 7 Apr 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Cross-site request forgery (CSRF) vulnerability in Kagemai 0.8.8 allows remote attackers to hijack the authentication of administrators via unspecified vectors.

Weakness: CWE-352 (Cross-Site Request Forgery)

## Which versions are affected by CVE-2021-20687?

It affects 1 product.


Products: Daifukuya Kagemai.

## How do I fix CVE-2021-20687?

No fix has been published for CVE-2021-20687 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-20687 being exploited?

There is no known exploitation of CVE-2021-20687 in the wild and no public exploit code.

## Other vulnerabilities in daifukuya.com Kagemai

- [CVE-2021-20685](https://insights.sbomify.com/CVE-2021-20685/): Cross-site scripting in Kagemai (medium 6.1)
- [CVE-2021-20686](https://insights.sbomify.com/CVE-2021-20686/): Cross-site scripting in Kagemai (medium 6.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-20687 and fix it if it is affected.

What it is: CVE-2021-20687 is a high-severity vulnerability in daifukuya.com Kagemai, published on 7 Apr 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-20687 in the wild and no public exploit code.

Affected product: daifukuya.com Kagemai. 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-2021-20687/ (Markdown: https://insights.sbomify.com/CVE-2021-20687/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-20687
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-20687
- OSV: https://osv.dev/vulnerability/CVE-2021-20687

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-20687/
Summaries are generated and may contain mistakes; the official description above is the record.