Vulnerability · Published Sep 29, 2025 · Assigned by CERT-PL
CVE-2025-9648Denial of Service in CivetWeb
High 8.7
In plain English
A high-severity security flaw in CivetWeb from CivetWeb. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.8% (higher than 55% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
A vulnerability in the CivetWeb library's function mg_handle_form_request allows remote attackers to trigger a denial of service (DoS) condition. By sending a specially crafted HTTP POST request containing a null byte in the payload, the server enters an infinite loop during form data parsing. Multiple malicious requests will result in complete CPU exhaustion and render the service unresponsive to further requests. This issue was fixed in commit 782e189. This issue affects only the library, standalone executable pre-built by vendor is not affected.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | civetweb | no fix listed | DEBIAN-CVE-2025-9648 |
| Debian:13 | civetweb | 1.16+dfsg-2+deb13u1 | DEBIAN-CVE-2025-9648 |
| Debian:14 | civetweb | 1.16+dfsg-4 | DEBIAN-CVE-2025-9648 |
| Ubuntu:24.04:LTS | civetweb | 1.16+dfsg-1ubuntu0.1 | USN-8749-1 |
| Ubuntu:24.04:LTS | civetweb | 1.16+dfsg-1ubuntu0.1 | UBUNTU-CVE-2025-9648 |
| Ubuntu:25.10 | civetweb | no fix listed | UBUNTU-CVE-2025-9648 |
| Ubuntu:26.04:LTS | civetweb | 1.16+dfsg-3ubuntu0.1 | UBUNTU-CVE-2025-9648 |
| Ubuntu:26.04:LTS | civetweb | 1.16+dfsg-3ubuntu0.1 | USN-8749-1 |
| Ubuntu:26.10 | civetweb | no fix listed | UBUNTU-CVE-2025-9648 |
Affected products (as reported)
Weakness: CWE-158 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N