# CVE-2024-3961: ConvertKit <= 2.4.9 - Missing Authorization

> Unauthenticated attackers can subscribe users to tags, potentially causing financial damage via API quota exhaustion.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 21 Jun 2024
- **Updated:** 8 Apr 2026
- **Also known as:** GHSA-x26g-933q-fggm

## What is CVE-2024-3961?

CVE-2024-3961 is a medium-severity missing authorization vulnerability in Kit (formerly ConvertKit) – Email Newsletter, Email Marketing, Membership, Subscribers and Landing Pages, published on 21 Jun 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The ConvertKit – Email Newsletter, Email Marketing, Subscribers and Landing Pages plugin for WordPress is vulnerable to unauthorized modification of data due to a missing capability check on the tag_subscriber function in all versions up to, and including, 2.4.9. This makes it possible for unauthenticated attackers to subscribe users to tags. Financial damages may occur to site owners if their API quota is exceeded.

Weakness: CWE-862 (Missing Authorization)

## Which versions are affected by CVE-2024-3961?

It affects 1 product.


Products: Convertkit Convertkit - Email Marketing\, Email Newsletter and Landing Pages.

## How do I fix CVE-2024-3961?

No fix has been published for CVE-2024-3961 yet. Limit exposure of the affected software until one is available.

## Is CVE-2024-3961 being exploited?

There is no known exploitation of CVE-2024-3961 in the wild and no public exploit code.

## Other vulnerabilities in Kit (formerly ConvertKit) – Email Newsletter, Email Marketing, Membership, Subscribers and Landing Pages

- [CVE-2023-2337](https://insights.sbomify.com/CVE-2023-2337/): ConvertKit < 2.2.1 - Reflected XSS (medium 6.1)
- [CVE-2022-4508](https://insights.sbomify.com/CVE-2022-4508/): ConvertKit < 2.0.5 - Contributor+ Stored XSS (medium 5.4)
- [CVE-2024-31245](https://insights.sbomify.com/CVE-2024-31245/): WordPress ConvertKit plugin <= 2.4.5 - Email Disclosure in Log File vulnerability (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-3961 and fix it if it is affected.

What it is: CVE-2024-3961 is a medium-severity missing authorization vulnerability in Kit (formerly ConvertKit) – Email Newsletter, Email Marketing, Membership, Subscribers and Landing Pages, published on 21 Jun 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2024-3961 in the wild and no public exploit code.

Affected product: Kit (formerly ConvertKit) – Email Newsletter, Email Marketing, Membership, Subscribers and Landing Pages. 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-2024-3961/ (Markdown: https://insights.sbomify.com/CVE-2024-3961/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-3961
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-3961
- OSV: https://osv.dev/vulnerability/CVE-2024-3961

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From sbomify Insights: https://insights.sbomify.com/CVE-2024-3961/
Summaries are generated and may contain mistakes; the official description above is the record.