{"id":"CVE-2026-29035","title":"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 …","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 …","severity":"medium","cvss":6.5,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H","cwe":["CWE-787"],"published":"2026-08-11","updated":"2026-09-24","sourceUpdated":"2026-09-24T20:32:04.063","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-29035","references":[{"url":"https://github.com/civetweb/civetweb","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/civetweb-heap-stack-buffer-overflow-via-websocket-permessage-deflate-decompression","label":"disclosure@vulncheck.com"}],"tags":["nvd"],"epss":0.00612,"epssPercentile":0.46997,"ingestedAt":"2026-09-24T20:51:40.196Z","slug":"CVE-2026-29035","body":"## Overview\n\nCivetWeb (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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":36,"depthScoreParts":{"impact":35.8,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}