{"id":"CVE-2026-21883","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-21883","generatedAt":"2026-10-28T08:10:47.628Z","title":"In versions 3.8.1 and below, if a server is configured with an allowlist (e.g., dashboard.corp), an attacker can register a domain like dashboard.corp.attacker.com (or use a subdomain if applicable) and lure a victim to visit it.","description":"Bokeh is an interactive visualization library written in Python. In versions 3.8.1 and below, if a server is configured with an allowlist (e.g., dashboard.corp), an attacker can register a domain like dashboard.corp.attacker.com (or use a subdomain if applicable) and lure a victim to visit it. The malicious site can then initiate a WebSocket connection to the vulnerable Bokeh server. Since the Origin header (e.g., http://dashboard.corp.attacker.com/) matches the allowlist according to the flawed logic, the connection is accepted. Once connected, the attacker can interact with the Bokeh server on behalf of the victim, potentially accessing sensitive data, or modifying visualizations. This issue is fixed in version 3.8.2.","published":"2026-01-08T02:15:54.000Z","lastModified":"2026-06-17T10:19:05.000Z","status":"Analyzed","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"4.0","score":4.5,"severity":"MEDIUM","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M"},"cwe":["CWE-1385"],"affected":["bokeh/bokeh"],"epss":{"score":0.00176,"percentile":0.07086,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.18%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://github.com/bokeh/bokeh/commit/cedd113b0e271b439dce768671685cf5f861812e","tags":["Patch"],"source":"security-advisories@github.com"},{"url":"https://github.com/bokeh/bokeh/security/advisories/GHSA-793v-589g-574v","tags":["Exploit","Vendor Advisory"],"source":"security-advisories@github.com"},{"url":"https://aydinnyunus.github.io/2026/01/24/bokeh-websocket-hijacking-cve-2026-21883/","tags":["Exploit","Mitigation","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-21883","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}