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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.

PUBLISHED Reserved 2025-08-29 | Published 2025-09-29 | Updated 2025-09-29 | Assigner CERT-PL




HIGH: 8.7CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Problem types

CWE-158 Improper Neutralization of Null Byte or NUL Character

Product status

Default status
unaffected

Any version before 1.08
unaffected

1.08 before 1.10
unknown

1.10
affected

Credits

Artur Łącki finder

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/...ommit/782e18903515f43bafbf2e668994e82bdfa51133 patch

cve.org (CVE-2025-9648)

nvd.nist.gov (CVE-2025-9648)

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