CivetWeb up to 1.16 HTTP POST Request mg_handle_form_request null byte or nul character

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
5.3	$0-$5k	0.00

Summaryinfo

A vulnerability categorized as problematic has been discovered in CivetWeb up to 1.16. This impacts the function mg_handle_form_request of the component HTTP POST Request Handler. Executing a manipulation can lead to improper neutralization of null byte or nul character. This vulnerability is handled as CVE-2025-9648. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability has been found in CivetWeb up to 1.16 and classified as problematic. This vulnerability affects the function mg_handle_form_request of the component HTTP POST Request Handler. The manipulation with an unknown input leads to a improper neutralization of null byte or nul character vulnerability. The CWE definition for the vulnerability is CWE-158. The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes NUL characters or null bytes when they are sent to a downstream component. As an impact it is known to affect availability. CVE summarizes:

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.

The weakness was released by Artur Łącki. The advisory is shared for download at cert.pl. This vulnerability was named CVE-2025-9648 since 08/29/2025. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 266288 (Linux Distros Unpatched Vulnerability : CVE-2025-9648), which helps to determine the existence of the flaw in a target environment.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at Tenable (266288). Once again VulDB remains the best source for vulnerability data.

Productinfo

Name

• CivetWeb

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9
• 1.10
• 1.11
• 1.12
• 1.13
• 1.14
• 1.15
• 1.16

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 5.3

VulDB Base Score: 5.3
VulDB Temp Score: 5.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
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💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Improper neutralization of null byte or nul character
CWE: CWE-158 / CWE-20
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 266288
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2025-9648

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

08/29/2025 CVE reserved
09/29/2025 +31 days Advisory disclosed
09/29/2025 +0 days VulDB entry created
10/02/2025 +3 days VulDB entry last update

Sourcesinfo

Advisory: cert.pl
Researcher: Artur Łącki
Status: Confirmed

CVE: CVE-2025-9648 (🔒)
GCVE (CVE): GCVE-0-2025-9648
GCVE (VulDB): GCVE-100-326236

Entryinfo

Created: 09/29/2025 14:13
Updated: 10/02/2025 13:11
Changes: 09/29/2025 14:13 (65), 10/02/2025 13:11 (2)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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