{"id":"CVE-2026-55040","aliases":["EUVD-2026-44211","GHSA-grxw-7cvc-96rv"],"status":"published","title":"Microsoft SharePoint Server Security Feature Bypass Vulnerability","description":"Weak authentication in Microsoft Office SharePoint allows an unauthorized attacker to bypass a security feature over a network.","severity":{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C","level":"critical","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.69536,"percentile":0.99372,"model":"v2026.06.15"},"facts":{"in_kev":true,"known_exploited":true,"public_exploit":true,"fix_available":false},"cwes":["CWE-1390"],"published":"2026-07-14T17:09:00Z","modified":"2026-11-01T17:36:32Z","kev":{"date_added":"2026-08-18","due_date":"2026-08-21","required_action":"Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.","known_ransomware_use":"Unknown"},"exploitation":[{"source":"euvd","since":"2026-08-18"},{"source":"kev","since":"2026-08-18"}],"exploits":[{"source":"pocgithub","id":"l0ggg/CVE-2026-55040","title":"l0ggg/CVE-2026-55040","date":"2026-07-28","url":"https://github.com/l0ggg/CVE-2026-55040"},{"source":"pocgithub","id":"sfewer-r7/CVE-2026-55040","title":"sfewer-r7/CVE-2026-55040","date":"2026-08-06","url":"https://github.com/sfewer-r7/CVE-2026-55040"},{"source":"pocgithub","id":"zenzue/CVE-2026-55040","title":"zenzue/CVE-2026-55040","date":"2026-08-26","url":"https://github.com/zenzue/CVE-2026-55040"},{"source":"pocgithub","id":"maxprog-svg/CVE-2026-55040-Mass-Exploit","title":"maxprog-svg/CVE-2026-55040-Mass-Exploit","date":"2026-08-27","url":"https://github.com/maxprog-svg/CVE-2026-55040-Mass-Exploit"},{"source":"pocgithub","id":"virologi-info/mssharepoint-scanner","title":"virologi-info/mssharepoint-scanner","date":"2026-08-27","url":"https://github.com/virologi-info/mssharepoint-scanner"},{"source":"nuclei","id":"CVE-2026-55040","title":"Microsoft SharePoint Server - JWT Authentication Bypass","type":"detection template","url":"https://github.com/projectdiscovery/nuclei-templates/blob/main/javascript/cves/2026/CVE-2026-55040.yaml"}],"products":[{"vendor":"microsoft","product":"microsoft sharepoint enterprise server 2016"},{"vendor":"microsoft","product":"microsoft sharepoint server 2019"},{"vendor":"microsoft","product":"microsoft sharepoint server subscription edition"},{"vendor":"microsoft","product":"sharepoint"},{"vendor":"microsoft","product":"sharepoint_server"}],"references":[{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55040","tags":["vendor-advisory","patch","Patch","Vendor Advisory"]},{"url":"https://www.rapid7.com/blog/post/ra-microsoft-sharepoint-jwt-token-authentication-bypass-cve-2026-55040/","tags":["technical-description","US Government Resource"]},{"url":"https://github.com/sfewer-r7/CVE-2026-55040","tags":["exploit","Exploit"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-55040","tags":["government-resource","Exploit","Third Party Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55040"},{"url":"https://www.rapid7.com/blog/post/ra-microsoft-sharepoint-jwt-token-authentication-bypass-cve-2026-55040"},{"url":"https://github.com/advisories/GHSA-grxw-7cvc-96rv"}],"sources":{"cve":[{"id":"CVE-2026-55040","title":"Microsoft SharePoint Server Security Feature Bypass Vulnerability","description":"Weak authentication in Microsoft Office SharePoint allows an unauthorized attacker to bypass a security feature over a network.","status":"published","published":"2026-07-14T17:09:00.641Z","modified":"2026-11-10T22:39:34.284Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C","level":"critical","assessor":"cna"}],"cwes":["CWE-1390"],"updated_at":"2026-11-10T23:49:29.755102Z"}],"euvd":[{"id":"EUVD-2026-44211","description":"Weak authentication in Microsoft Office SharePoint allows an unauthorized attacker to bypass a security feature over a network.","status":"published","published":"2026-07-14T17:09:00Z","modified":"2026-11-10T22:39:34Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C","level":"critical"}],"exploited_since":"2026-08-18","updated_at":"2026-11-11T00:24:47.005432Z"}],"ghsa":[{"id":"GHSA-grxw-7cvc-96rv","title":"Weak authentication in Microsoft Office SharePoint allows an unauthorized attacker to bypass a...","description":"Weak authentication in Microsoft Office SharePoint allows an unauthorized attacker to bypass a security feature over a network.","status":"published","published":"2026-07-14T18:32:33Z","modified":"2026-08-18T18:32:50Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical"}],"cwes":["CWE-1390"],"updated_at":"2026-11-02T15:10:37.069016Z"}],"kev":[{"id":"CVE-2026-55040","title":"Microsoft SharePoint Weak Authentication Vulnerability","description":"Microsoft SharePoint contains a weak authentication vulnerability which allows an unauthorized attacker to bypass a security feature over a network.","cwes":["CWE-1390"],"kev":{"date_added":"2026-08-18","due_date":"2026-08-21","required_action":"Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.","known_ransomware_use":"Unknown"},"updated_at":"2026-11-02T17:00:15.999436Z"}],"nvd":[{"id":"CVE-2026-55040","description":"Weak authentication in Microsoft Office SharePoint allows an unauthorized attacker to bypass a security feature over a network.","status":"published","published":"2026-07-14T18:18:15.413Z","modified":"2026-08-19T04:17:23.54Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical","assessor":"secondary"}],"cwes":["CWE-1390"],"updated_at":"2026-11-02T14:12:29.489525Z"}]}}