Vulnerability in Civetweb
CVE-2025-9648
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.
Published · last modified .
EPSS exploit prediction
EPSS: 0.008 (53.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 54th percentile — 53.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: 0.000
Affected products
- Civetweb — versions 0, 1.08, 1.10
Weakness classification (CWE)
Public proof-of-concept exploits
References
- cert.pl/en/posts/2025/09/CVE-2025-9648 (third-party-advisory)
- github.com/civetweb/civetweb (product)
- github.com/civetweb/civetweb/issues/1348 (issue-tracking)
- github.com/civetweb/civetweb/commit/782e18903515f43bafbf2e668994e82bdfa51133 (patch)
Frequently asked questions
- What is CVE-2025-9648?
- CVE-2025-9648 is a vulnerability in Civetweb, classified under CWE-158. Published 2025-09-29.
- Is CVE-2025-9648 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.