Improper Neutralization of Null Byte or NUL Character Affecting civetweb package, versions *


Severity

Recommended
low

Based on Debian security rating.

Threat Intelligence

EPSS
0.76% (53rd percentile)

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  • Snyk IDSNYK-DEBIAN12-CIVETWEB-13148109
  • published30 Sept 2025
  • disclosed29 Sept 2025

Introduced: 29 Sep 2025

CVE-2025-9648  (opens in a new tab)
CWE-158  (opens in a new tab)

How to fix?

There is no fixed version for Debian:12 civetweb.

NVD Description

Note: Versions mentioned in the description apply only to the upstream civetweb package and not the civetweb package as distributed by Debian. See How to fix? for Debian:12 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.