{"id":"CVE-2021-39906","published":"2021-11-04T23:04:36Z","modified":"2024-08-04T02:20:33Z","title":"Improper validation of ipynb files in GitLab CE/EE version 13.5 and above allows an attacker to execute arbitrary…","vendor":"GitLab","product":"GitLab","tier":"core","eol":null,"affectedVersions":[{"vendor":"GitLab","product":"GitLab","versions":[">=13.5, <14.2.6",">=14.3, <14.3.4",">=14.4, <14.4.1"]}],"description":{"text":"Improper validation of ipynb files in GitLab CE/EE version 13.5 and above allows an attacker to execute arbitrary JavaScript code on the victim's behalf.","provenance":"source","from":"CVE.org"},"summary":{"text":"The flaw is improper validation of ipynb (Jupyter notebook) files in GitLab CE/EE, affecting version 13.5 and above. An attacker who gets a victim to interact with a malicious notebook can execute arbitrary JavaScript in the victim's browser session, acting on their behalf; this requires network access, low privileges, and user interaction, and the scope changes beyond the vulnerable component.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-29T07:15:53Z"},"cvss":{"score":8.7,"severity":"HIGH","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N","provenance":"source","from":"CVE.org CNA"},"epss":{"score":0.60729,"percentile":0.99145,"date":"2026-10-29","provenance":"source"},"kev":null,"vulncheckKev":null,"exploited":false,"otx":{"pulseCount":0,"pulses":[],"provenance":"machine"},"cwes":[],"references":[{"url":"https://gitlab.com/gitlab-org/gitlab/-/issues/341566","tags":["x_refsource_MISC"]},{"url":"https://hackerone.com/reports/1347600","tags":["x_refsource_MISC"]},{"url":"https://gitlab.com/gitlab-org/cves/-/blob/master/2021/CVE-2021-39906.json","tags":["x_refsource_CONFIRM"]}],"techniques":[],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2021-26262","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2021-26262","exploited":false,"exploitedSince":null,"provenance":"source"},"exploits":[],"exploitSources":null,"exploitRefs":[],"flow":[],"timeline":[{"date":"2021-11-04","kind":"published","label":"Published (CVE.org)","url":"https://www.cve.org/CVERecord?id=CVE-2021-39906","provenance":"source"}],"speed":{"daysToPublicExploit":null,"firstExploitFrom":null,"daysToKev":null},"priority":{"score":25.9,"factors":[{"name":"In a KEV catalog","points":0.0,"detail":"not listed"},{"name":"Recent KEV listing","points":0.0,"detail":"not listed"},{"name":"Known ransomware use","points":0.0,"detail":"not known"},{"name":"EPSS percentile","points":19.83,"detail":"percentile 0.9915"},{"name":"Named in threat reports","points":0.0,"detail":"0 reports"},{"name":"Public exploit code","points":0.0,"detail":"none found"},{"name":"Mentioned in OTX pulses","points":0.0,"detail":"0 pulses"},{"name":"CVSS severity","points":6.09,"detail":"base score 8.7"},{"name":"End-of-life product","points":0.0,"detail":"supported or unknown"}]}}