CVE-2026-29035
MediumCVSS 6.5Exploitation Probability (EPSS)
Low risk38th percentile - higher than 38% of all known CVEs
Summary
CivetWeb (commit 4a4f0c95) contains a heap and stack buffer overflow vulnerability in the read_websocket() function that allows unauthenticated remote attackers to corrupt memory by sending compressed WebSocket frames when both USE_ZLIB and MG_EXPERIMENTAL_INTERFACES are defined. Attackers can negotiate permessage-deflate during the WebSocket handshake and send a crafted frame with the RSV1 bit set, causing the server to write a 4-byte zlib sync trailer out-of-bounds past the allocated buffer, leading to heap metadata corruption, denial of service, or potential code execution.
Risk Assessment
The risk includes remote memory corruption, potentially leading to denial of service or remote code execution. This may compromise confidentiality, integrity, and availability of the system.
Recommendation
It is recommended to immediately upgrade CivetWeb to a patched version or apply a workaround if available. Also monitor project security advisories.
Original NVD description (English source)
CivetWeb (commit 4a4f0c95) contains a heap and stack buffer overflow vulnerability in the read_websocket() function that allows unauthenticated remote attackers to corrupt memory by sending compressed WebSocket frames when both USE_ZLIB and MG_EXPERIMENTAL_INTERFACES are defined. Attackers can negotiate permessage-deflate during the WebSocket handshake and send a crafted frame with the RSV1 bit set, causing the server to write a 4-byte zlib sync trailer out-of-bounds past the allocated buffer, leading to heap metadata corruption, denial of service, or potential code execution.