# CVE-2023-27100: Security feature bypass in n/a

> Attackers can bypass SSHGuard brute force protection in pfSense via crafted web requests, allowing continued authentication attempts.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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:** Not needed
- **Fix available:** No
- **Published:** 22 Mar 2023
- **Updated:** 25 Feb 2025
- **Also known as:** GHSA-wmh3-5pfq-qpp8

## What is CVE-2023-27100?

CVE-2023-27100 is a critical vulnerability in n/a, published on 22 Mar 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Improper restriction of excessive authentication attempts in the SSHGuard component of Netgate pfSense Plus software v22.05.1 and pfSense CE software v2.6.0 allows attackers to bypass brute force protection mechanisms via crafted web requests.

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

## Which versions are affected by CVE-2023-27100?

It affects 2 products.


Products: Netgate Pfsense Plus, Pfsense Pfsense.

## How do I fix CVE-2023-27100?

No fix has been published for CVE-2023-27100 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-27100 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-27100 exists.

Public exploit code:

- pfsenseCE v2.6.0 - Anti-brute force protection bypass (exploitdb)
- https://github.com/fabdotnet/CVE-2023-27100 (github_poc): https://github.com/fabdotnet/CVE-2023-27100

## Other vulnerabilities in n/a

- [CVE-2021-20729](https://insights.sbomify.com/CVE-2021-20729/): Cross-site scripting in pfSense CE and pfSense Plus (medium 6.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-27100 and fix it if it is affected.

What it is: CVE-2023-27100 is a critical vulnerability in n/a, published on 22 Mar 2023. 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-2023-27100 exists.

Affected product: n/a. 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-2023-27100/ (Markdown: https://insights.sbomify.com/CVE-2023-27100/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-27100
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-27100
- OSV: https://osv.dev/vulnerability/CVE-2023-27100

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-27100/
Summaries are generated and may contain mistakes; the official description above is the record.