# CVE-2025-1731: Privilege escalation in USG FLEX H series uOS firmware

> Authenticated low-privilege users can escalate to administrator access and execute code via incorrect permission assignments in Zyxel USG FLEX H firmware.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 22 Apr 2025
- **Updated:** 26 Feb 2026
- **Also known as:** GHSA-2w3x-653c-q4pc

## What is CVE-2025-1731?

CVE-2025-1731 is a high-severity vulnerability in Zyxel USG FLEX H series uOS firmware, published on 22 Apr 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

An incorrect permission assignment vulnerability in the PostgreSQL commands of the Zyxel USG FLEX H series uOS firmware versions from V1.20 through V1.31 could allow an authenticated local attacker with low privileges to gain access to the Linux shell and escalate their privileges by crafting malicious scripts or modifying system configurations with administrator-level access through a stolen token. Modifying the system configuration is only possible if the administrator has not logged out and the token remains valid.

Weakness: CWE-732 (Incorrect Permission Assignment for Critical Resource)

## Which versions are affected by CVE-2025-1731?

It affects 1 product.


Products: Zyxel Uos.

## How do I fix CVE-2025-1731?

No fix has been published for CVE-2025-1731 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-1731 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-1731 exists.

Public exploit code:

- Zyxel USG FLEX H series uOS 1.31 - Privilege Escalation (exploitdb)

## Other vulnerabilities in Zyxel USG FLEX H series uOS firmware

- [CVE-2025-1732](https://insights.sbomify.com/CVE-2025-1732/): Privilege escalation in USG FLEX H series uOS firmware (medium 6.7)
- [CVE-2024-9677](https://insights.sbomify.com/CVE-2024-9677/): Information disclosure in USG FLEX H series uOS firmware (medium 5.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-1731 and fix it if it is affected.

What it is: CVE-2025-1731 is a high-severity vulnerability in Zyxel USG FLEX H series uOS firmware, published on 22 Apr 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-1731 exists.

Affected product: Zyxel USG FLEX H series uOS firmware. 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-2025-1731/ (Markdown: https://insights.sbomify.com/CVE-2025-1731/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-1731
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-1731
- OSV: https://osv.dev/vulnerability/CVE-2025-1731

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-1731/
Summaries are generated and may contain mistakes; the official description above is the record.