{"id":"JLSEC-2026-101","details":"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.","modified":"2026-07-25T18:23:46.593550844Z","published":"2026-04-14T13:10:46.494Z","upstream":["CVE-2023-26103"],"database_specific":{"sources":[{"html_url":"https://nvd.nist.gov/vuln/detail/CVE-2023-26103","database_specific":{"status":"Modified"},"id":"CVE-2023-26103","imported":"2026-07-17T21:08:38.099Z","modified":"2026-06-17T05:42:41.007Z","published":"2023-02-25T05:15:12.343Z","url":"https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2023-26103"}],"license":"CC-BY-4.0"},"references":[{"type":"WEB","url":"https://github.com/denoland/deno/blob/2b247be517d789a37e532849e2e40b724af0918f/ext/http/01_http.js%23L395-L409"},{"type":"WEB","url":"https://github.com/denoland/deno/commit/cf06a7c7e672880e1b38598fe445e2c50b4a9d06"},{"type":"WEB","url":"https://github.com/denoland/deno/pull/17722"},{"type":"WEB","url":"https://github.com/denoland/deno/releases/tag/v1.31.0"},{"type":"WEB","url":"https://security.snyk.io/vuln/SNYK-RUST-DENO-3315970"}],"affected":[{"package":{"name":"Deno_jll","ecosystem":"Julia","purl":"pkg:julia/Deno_jll?uuid=04572ae6-984a-583e-9378-9577a1c2574d"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.33.4+0"}]}],"database_specific":{"source":"https://github.com/JuliaLang/SecurityAdvisories.jl/tree/generated/osv/2026/JLSEC-2026-101.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}