Improper Neutralization of Null Byte or NUL Character Affecting civetweb package, versions <1.16+dfsg-2+deb13u1


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.76% (53rd percentile)

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  • Snyk IDSNYK-DEBIAN13-CIVETWEB-13148105
  • 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?

Upgrade Debian:13 civetweb to version 1.16+dfsg-2+deb13u1 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 Debian. See How to fix? for Debian:13 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.