# CVE-2026-58123: Hermes WebUI < 0.51.788 Unauthenticated RCE via Terminal API

> Unauthenticated attackers can execute arbitrary shell commands via the terminal API, leading to full remote code execution on the server.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/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:** 9 Jul 2026
- **Updated:** 14 Jul 2026
- **Also known as:** GHSA-ph29-g65g-m574

## What is CVE-2026-58123?

CVE-2026-58123 is a critical command injection vulnerability in nesquena hermes-webui, published on 9 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Hermes WebUI before 0.51.788 contains an unauthenticated remote code execution vulnerability that allows remote attackers to execute arbitrary shell commands by accessing the embedded terminal API endpoints without credentials. Attackers can create a session, attach a PTY shell, and write arbitrary commands through the terminal input endpoint to achieve full command execution as the server process user via four sequential unauthenticated HTTP requests.

Weakness: CWE-306 (Missing Authentication for Critical Functionality)

## Which versions are affected by CVE-2026-58123?


## How do I fix CVE-2026-58123?

No fix has been published for CVE-2026-58123 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-58123 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-58123 exists.

Public exploit code:

- Hermes WebUI < 0.51.788 - Remote Code Execution (nuclei): http/cves/2026/CVE-2026-58123.yaml

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-58123 and fix it if it is affected.

What it is: CVE-2026-58123 is a critical command injection vulnerability in nesquena hermes-webui, published on 9 Jul 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-2026-58123 exists.

Affected product: nesquena hermes-webui. 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-2026-58123/ (Markdown: https://insights.sbomify.com/CVE-2026-58123/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-58123
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-58123
- OSV: https://osv.dev/vulnerability/CVE-2026-58123

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-58123/
Summaries are generated and may contain mistakes; the official description above is the record.