# CVE-2026-123040: Privilege escalation in TrueConf Server

> An attacker able to run code as the trueconf user can escalate to root on Linux TrueConf Server hosts.

- **Severity:** High 8.5 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Harmful if only installed:** Yes
- **Needs a specific call:** No
- **Fix available:** No
- **Published:** 11 Nov 2026
- **Updated:** 12 Nov 2026
- **Also known as:** GHSA-93qv-qx6g-2cv6

## What is CVE-2026-123040?

CVE-2026-123040 is a high-severity privilege escalation vulnerability in TrueConf Server, published on 11 Nov 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

An attacker who gains the ability to execute arbitrary code on a system with TrueConf Server (Linux) versions from 4.7.2 up to, but not including, 5.5.6 installed, running as the user trueconf (by exploiting some other vulnerability), can elevate their privileges to root.

Weakness: CWE-276 (Incorrect Default Permissions)

## Which versions are affected by CVE-2026-123040?

Having an affected version installed is enough. The problem is in what it ships or how it installs, so no code has to call it.


## How do I fix CVE-2026-123040?

No fix has been published for CVE-2026-123040 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-123040 being exploited?

There is no known exploitation of CVE-2026-123040 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-123040 and fix it if it is affected.

What it is: CVE-2026-123040 is a high-severity privilege escalation vulnerability in TrueConf Server, published on 11 Nov 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-123040 in the wild and no public exploit code.
Exposure: Having an affected version installed is enough. The problem is in what it ships or how it installs, so no code has to call it.

Affected product: TrueConf Server. 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-2026-123040/ (Markdown: https://insights.sbomify.com/CVE-2026-123040/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-123040
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-123040
- OSV: https://osv.dev/vulnerability/CVE-2026-123040

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-123040/
Summaries are generated and may contain mistakes; the official description above is the record.