A critical vulnerability identified as CVE-2026-124040 has been discovered in CivetWeb versions 1.13 to 1.16. This use-after-free vulnerability affects the handling of HTTP/2 headers, potentially allowing unauthenticated remote attackers to manipulate request methods and paths.
The vulnerability, published on November 6, 2026, carries a CVSS score of 9.2, indicating a high severity level. It poses a significant risk, particularly to internet-facing deployments and embedded applications using CivetWeb.
While no active exploitation has been confirmed, the potential for remote code execution under specific conditions remains a concern. Users are advised to be vigilant and monitor for unusual HTTP/2 traffic.
CivetWeb users should prepare for patching once a fix becomes available. Until then, maintaining heightened awareness of network activity is recommended to mitigate potential risks.