{"cve":"CVE-2023-26103","nvd":{"published":"2023-02-25T05:15:12.343","modified":"2026-06-17T05:42:41.007","status":"Modified","description":"Versions of the package deno before 1.31.0 are vulnerable to Regular Expression Denial of Service (ReDoS) due to the upgradeWebSocket function, which contains regexes in the form of /s*,s*/, used for splitting the Connection/Upgrade header. A specially crafted Connection/Upgrade header can be used to significantly slow down a web socket server.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-1333"],"references":["https://github.com/denoland/deno/blob/2b247be517d789a37e532849e2e40b724af0918f/ext/http/01_http.js%23L395-L409","https://github.com/denoland/deno/commit/cf06a7c7e672880e1b38598fe445e2c50b4a9d06","https://github.com/denoland/deno/pull/17722","https://github.com/denoland/deno/releases/tag/v1.31.0","https://security.snyk.io/vuln/SNYK-RUST-DENO-3315970"],"products":["deno:deno"],"source":"nvd","synced_at":"2026-10-19T21:37:41.955480748+00:00"},"epss":{"cve":"CVE-2023-26103","score":0.01229,"percentile":0.68917,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-jc97-h3h9-7xh6","url":"https://osv.dev/vulnerability/GHSA-jc97-h3h9-7xh6","summary":"Regular Expression Denial of Service in Deno.upgradeWebSocket API","modified":"2023-11-08T04:11:57.713363Z","packages":[{"ecosystem":"crates.io","name":"deno","purl":"pkg:cargo/deno","ranges":[">=1.12.0 <1.31.0"],"fixed":["1.31.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}