- Critical 9.1
- Known exploited (CISA KEV)
CVE-2026-55040
Weak authentication in Microsoft Office SharePoint allows an unauthorized attacker to bypass a security feature over a network.
Scores
The facts
- Published
- 14 July 2026
- Last changed
- 19 August 2026
- NVD status
- Analyzed
- Severity
- Critical, CVSS 9.1 out of 10 (version 3.1)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - Weakness
- Affects
- microsoft sharepoint server
- Known exploited
- Yes. CISA added it to the Known Exploited Vulnerabilities catalogue on 18 August 2026.
- EPSS
- 69.5% chance of exploitation activity in the next 30 days (percentile 99).
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