CVE-2025-9648

Denial of Service in CivetWeb

State: Published
Severity: 8.7 High
Published: Sep 29, 2025
Updated: Sep 29, 2025
Reserved: Aug 29, 2025

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.

Scores

CVSS	Score	Vector	Source
4.0	8.7 High	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	CERT-PL

Weaknesses

CWE-158 Improper Neutralization of Null Byte or NUL Character

Affected Products

Product	Versions
CivetWebCivetWeb	before 1.08Not affected 1.08 to before 1.10Unknown 1.10 through 1.16Affected

References

https://cert.pl/en/posts/2025/09/CVE-2025-9648third-party-advisory
https://github.com/civetweb/civetwebproduct
https://github.com/civetweb/civetweb/issues/1348issue-tracking
https://github.com/civetweb/civetweb/commit/782e18903515f43bafbf2e668994e82bdfa51133patch

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