# CVE-2026-73529: Plainpad Missing Rate Limiting via POST /v1/sessions

> Unauthenticated attackers can exhaust CPU resources and bypass login protections in Plainpad due to missing rate limiting on the session endpoint.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 18 Aug 2026
- **Updated:** 18 Aug 2026
- **Also known as:** GHSA-9fxw-r4jg-3hq3

## What is CVE-2026-73529?

CVE-2026-73529 is a medium-severity denial of service vulnerability in alextselegidis plainpad, published on 18 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Plainpad through 1.1.1, fixed in commit d3823fc, contains a missing rate limiting vulnerability that allows unauthenticated attackers to send unbounded login requests to the POST /v1/sessions endpoint due to dead code in App\Http\Kernel.php that is never instantiated under the Laravel 11+ skeleton, leaving the API throttle configuration unattached to any route. Attackers can exploit this by sending unlimited credential attempts with no lockout or CAPTCHA enforcement, and additionally trigger CPU exhaustion by forcing repeated bcrypt comparisons on each request.

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

## Which versions are affected by CVE-2026-73529?


## How do I fix CVE-2026-73529?

No fix has been published for CVE-2026-73529 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-73529 being exploited?

There is no known exploitation of CVE-2026-73529 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-73529 and fix it if it is affected.

What it is: CVE-2026-73529 is a medium-severity denial of service vulnerability in alextselegidis plainpad, published on 18 Aug 2026. 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-2026-73529 in the wild and no public exploit code.

Affected product: alextselegidis plainpad. 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-2026-73529/ (Markdown: https://insights.sbomify.com/CVE-2026-73529/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-73529
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-73529
- OSV: https://osv.dev/vulnerability/CVE-2026-73529

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-73529/
Summaries are generated and may contain mistakes; the official description above is the record.