# CVE-2026-40586: blueprintUE: Login Endpoint Has No Rate Limiting, Lockout, or Brute-Force Protection

> Attackers can perform unlimited brute-force attacks on login endpoints due to missing rate limiting, potentially leading to account takeover.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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 Apr 2026
- **Updated:** 21 Apr 2026
- **Also known as:** GHSA-m6c2-6p3h-8jv2

## What is CVE-2026-40586?

CVE-2026-40586 is a high-severity missing authorization vulnerability in blueprintue-self-hosted-edition, published on 21 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

blueprintUE is a tool to help Unreal Engine developers. Prior to 4.2.0, the login form handler performs no throttling of any kind. Failed authentication attempts are processed at full network speed with no IP-based rate limiting, no per-account attempt counter, no temporary lockout, no progressive delay (Tarpit), and no CAPTCHA challenge. An attacker can submit an unlimited number of credential guesses. The password policy (10+ characters, mixed case, digit, special character) reduces the effective keyspace but does not prevent dictionary attacks, credential stuffing from breached databases, or targeted attacks against known users with predictable passwords. This vulnerability is fixed in 4.2.0.

Weakness: CWE-307 (Improper Restriction of Excessive Authentication Attempts)

## Which versions are affected by CVE-2026-40586?


## How do I fix CVE-2026-40586?

No fix has been published for CVE-2026-40586 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-40586 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40586 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-40586 and fix it if it is affected.

What it is: CVE-2026-40586 is a high-severity missing authorization vulnerability in blueprintue-self-hosted-edition, published on 21 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-40586 exists.

Affected product: blueprintue-self-hosted-edition. 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-2026-40586/ (Markdown: https://insights.sbomify.com/CVE-2026-40586/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-40586
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40586
- OSV: https://osv.dev/vulnerability/CVE-2026-40586

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-40586/
Summaries are generated and may contain mistakes; the official description above is the record.