Improper Neutralization of Null Byte or NUL Character Affecting civetweb package, versions <1.16+dfsg-3ubuntu0.1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-UBUNTU2604-CIVETWEB-16234398
- published14 Sept 2026
- disclosed29 Sept 2025
Introduced: 29 Sep 2025
CVE-2025-9648 (opens in a new tab)How to fix?
Upgrade Ubuntu:26.04 civetweb to version 1.16+dfsg-3ubuntu0.1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream civetweb package and not the civetweb package as distributed by Ubuntu.
See How to fix? for Ubuntu:26.04 relevant fixed versions and status.
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.