What’s Vulnerable › Vulnerabilities

CVE-2025-9648: Denial of Service in CivetWeb

• Severity: high (CVSS 8.7 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-09-29 · updated 2026-10-19
• Weakness: CWE-158

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.

Affected products

• CivetWeb: from 1.10 through 1.16

References

• https://cert.pl/en/posts/2025/09/CVE-2025-9648
• https://github.com/civetweb/civetweb
• https://github.com/civetweb/civetweb/commit/782e18903515f43bafbf2e668994e82bdfa51133
• https://github.com/civetweb/civetweb/issues/1348

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