CVE-2026-33029

Nginx UI: DoS via Negative Integer Input in Logrotate Interval

CVSS 4.0 6.9 MEDIUMEUVD CVSS 4.0 6.9 CVSS 4.0 · [email protected] · Secondary 6.9 MEDIUMCVSS 3.1 · [email protected] · Primary 6.5 MEDIUMCVSS 3.1 · 134c704f-9b21-4f2e-91b3-4a467353bcc0 · Secondary 6.5 MEDIUMCVSS_V4 Publisher rating MODERATEosv · severity unknownCheck source for fixed versionsKEV status unknown

Original advisory

cve-program · CVE-2026-33029

Published

Nginx UI is a web user interface for the Nginx web server. Prior to version 2.3.4, an input validation vulnerability in the logrotate configuration allows an authenticated user to cause a complete Denial of Service (DoS). By submitting a negative integer for the rotation interval, the backend enters an infinite loop or an invalid state, rendering the web interface unresponsive. This issue has been patched in version 2.3.4.

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euvd · EUVD-2026-17154

Published

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nvd · CVE-2026-33029

Published

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osv · GHSA-cp8r-8jvw-v3qg

Published

### Summary An input validation vulnerability in the logrotate configuration allows an authenticated user to cause a complete Denial of Service (DoS). By submitting a negative integer for the rotation interval, the backend enters an infinite loop or an invalid state, rendering the web interface unresponsive. ### Details The vulnerability exists in the handler for the POST /api/settings endpoint. Specifically, the logrotate.interval field is accepted as a signed integer without lower-bound verification. When a negative value is processed by the backend logic responsible for scheduling or calculating the next rotation, it triggers a non-terminating loop. This consumes CPU resources and prevents the Go web server from handling further concurrent requests. **Environment:** - OS: Kali Linux 6.17.10-1kali1 (6.17.10+kali-amd64) - nginx-ui version: 2.3.3 (513) e5da6dd (go1.26.0 linux/amd64) - Deployment: Docker container - Run Command: ``` docker run -dit \ --name=nginx-ui \ --restart=always \ -v /mnt/user4/appdata/nginx:/etc/nginx \ -v /mnt/user4/appdata/nginx-ui:/etc/nginx-ui \ -v /var/run/docker.sock:/var/run/docker.sock \ -p 8080:80 -p 8443:443 \ uozi/nginx-ui:latest ``` ### PoC 1. Authenticate to the nginx-ui dashboard. 2. Send a POST request to /api/settings (using Burp Suite, Postman, or curl). 3. Set the payload as follows: ``` . . . { "logrotate": { "enabled": true, "cmd": "logrotate /etc/logrotate.d/nginx", "interval": -1 } } . . . ``` 4. Observe that the web server stops responding to all subsequent requests immediately after the injection. <img width="1041" height="390" alt="image" src="https://github.com/user-attachments/assets/b746a91a-dd63-4f5e-b1a8-382b9d08e181" /> ### Impact This is a High-availability vulnerability (CWE-20: Improper Input Validation). Any authenticated user with access to settings can permanently hang the service. A patched version of nginx-ui is available at https://github.com/0xJacky/nginx-ui/releases/tag/v2.3.4.

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osv · GO-2026-4902

Published

nginx-ui Vulnerable to DoS via Negative Integer Input in Logrotate Interval in github.com/0xJacky/Nginx-UI

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Affected versions, risk and source history

Exploitation and risk

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Advisory history

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15 Nov 2026 09:36:48 UTC