{"cve":"CVE-2026-21883","nvd":{"published":"2026-01-08T02:15:53.950","modified":"2026-06-17T10:19:05.170","status":"Analyzed","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.","cvss_v4":{"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","score":4.5},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N","score":5.4},"cwes":["CWE-1385"],"references":["https://github.com/bokeh/bokeh/commit/cedd113b0e271b439dce768671685cf5f861812e","https://github.com/bokeh/bokeh/security/advisories/GHSA-793v-589g-574v","https://aydinnyunus.github.io/2026/01/24/bokeh-websocket-hijacking-cve-2026-21883/"],"products":["bokeh:bokeh"],"source":"nvd","synced_at":"2026-10-19T22:19:41.481987139+00:00"},"epss":{"cve":"CVE-2026-21883","score":0.00176,"percentile":0.07114,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-793v-589g-574v","url":"https://osv.dev/vulnerability/GHSA-793v-589g-574v","summary":"Bokeh server applications have Incomplete Origin Validation in WebSockets","modified":"2026-09-10T03:50:32.759807855Z","packages":[{"ecosystem":"PyPI","name":"bokeh","purl":"pkg:pypi/bokeh","ranges":["<3.8.2"],"fixed":["3.8.2"]}]},{"id":"PYSEC-2026-1223","url":"https://osv.dev/vulnerability/PYSEC-2026-1223","summary":"Bokeh server applications have Incomplete Origin Validation in WebSockets","modified":"2026-07-07T17:47:32.650537140Z","packages":[{"ecosystem":"PyPI","name":"bokeh","purl":"pkg:pypi/bokeh","ranges":["<3.8.2"],"fixed":["3.8.2"]}]}],"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."]}