{"id":"CVE-2026-27630","summary":"TinyWeb vulnerable to Remote Denial of Service via Thread/Connection Exhaustion (Slowloris)","details":"TinyWeb is a web server (HTTP, HTTPS) written in Delphi for Win32. Versions prior to version 2.02 are vulnerable to a Denial of Service (DoS) attack known as Slowloris. The server spawns a new OS thread for every incoming connection without enforcing a maximum concurrency limit or an appropriate request timeout. An unauthenticated remote attacker can exhaust server concurrency limits and memory by opening numerous connections and sending data exceptionally slowly (e.g. 1 byte every few minutes). Anyone hosting services using TinyWeb is impacted. Version 2.02 fixes the issue. The patch introduces a `CMaxConnections` limit (set to 512) and a `CConnectionTimeoutSecs` idle timeout (set to 30 seconds). As a temporary workaround if upgrading is not immediately possible, consider placing the server behind a robust reverse proxy or Web Application Firewall (WAF) such as nginx, HAProxy, or Cloudflare, configured to buffer incomplete requests and aggressively enforce connection limits and timeouts.","aliases":["GHSA-ccv5-8948-c99c"],"modified":"2026-08-12T03:51:19.136121389Z","published":"2026-02-25T23:05:16.563Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27630.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-400"]},"references":[{"type":"WEB","url":"https://www.masiutin.net/tinyweb-cve-2026-27630.html"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27630.json"},{"type":"ADVISORY","url":"https://github.com/maximmasiutin/TinyWeb/security/advisories/GHSA-ccv5-8948-c99c"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-27630"},{"type":"FIX","url":"https://github.com/maximmasiutin/TinyWeb/commit/23268c8"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/maximmasiutin/tinyweb","events":[{"introduced":"0"},{"fixed":"e09ebba3444d3aa5a081f49db51849deec2cd64e"},{"fixed":"23268c8"}],"database_specific":{"cpe":"cpe:2.3:a:ritlabs:tinyweb:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"0"},{"fixed":"2.02"}],"source":["CPE_RANGE","REFERENCES"]}}],"versions":["v2.01","v1.99","1.98","v1.98","v1.97","v1.96","v1.95"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-27630.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"}]}