CVE-2025-53771

medium

Description

Improper authentication in Microsoft Office SharePoint allows an unauthorized attacker to perform spoofing over a network.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-53771

https://www.bleepingcomputer.com/news/security/ransomware-gangs-join-attacks-targeting-microsoft-sharepoint-servers/

https://unit42.paloaltonetworks.com/microsoft-sharepoint-cve-2025-49704-cve-2025-49706-cve-2025-53770/

https://www.helpnetsecurity.com/2025/07/24/storm-2603-spotted-deploying-ransomware-on-exploited-sharepoint-servers/

https://cyberscoop.com/microsoft-sharepoint-attacks-400-victims-us-agencies/

https://securityaffairs.com/180267/apt/microsoft-linked-attacks-on-sharepoint-flaws-to-china-nexus-actors.html

https://www.theregister.com/2025/07/22/microsoft_sharepoint_2016_patch/

https://www.infosecurity-magazine.com/news/sharepoint-toolshell-chinese/

https://www.helpnetsecurity.com/2025/07/22/microsoft-pins-sharepoint-attacks-cve-2025-53770/

https://www.bleepingcomputer.com/news/security/microsoft-sharepoint-toolshell-attacks-linked-to-chinese-hackers/

https://www.axios.com/2025/07/22/microsoft-sharepoint-china-hack-targets

https://cyberscoop.com/microsoft-sharepoint-zero-days-china-typhoon/

https://www.hipaajournal.com/microsof-emergency-patches-sharepoint-server-vulnerabilities/

https://www.databreachtoday.com/attackers-exploit-zero-day-flaws-in-on-premises-sharepoint-a-29018

https://securityaffairs.com/180211/hacking/u-s-cisa-urges-to-immediately-patch-microsoft-sharepoint-flaw-adding-it-to-its-known-exploited-vulnerabilities-catalog.html

https://blog.talosintelligence.com/toolshell-affecting-sharepoint-servers/

https://msrc.microsoft.com/blog/2025/07/customer-guidance-for-sharepoint-vulnerability-cve-2025-53770/

https://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/echoes-in-the-shell-legacy-tooling-behind-ongoing-sharepoint-toolshell-exploitation/

https://www.theregister.com/2025/08/07/cisa_releases_malware_analysis/

https://securelist.com/toolshell-explained/117045/

https://www.welivesecurity.com/en/eset-research/toolshell-an-all-you-can-eat-buffet-for-threat-actors/

https://www.theregister.com/2025/07/24/microsoft_sharepoint_ransomware/

https://www.securityweek.com/toolshell-attacks-hit-400-sharepoint-servers-us-government-victims-named/

https://www.darkreading.com/endpoint-security/ransomware-actors-toolshell-sharepoint-bugs

https://www.securityweek.com/toolshell-zero-day-attacks-on-sharepoint-first-wave-linked-to-china-hit-high-value-targets/

https://www.securityweek.com/microsoft-says-chinese-apts-exploited-toolshell-zero-days-weeks-before-patch/

https://www.microsoft.com/en-us/security/blog/2025/07/22/disrupting-active-exploitation-of-on-premises-sharepoint-vulnerabilities/

https://www.darkreading.com/application-security/3-china-nation-state-actors-sharepoint-bugs

https://therecord.media/microsoft-sharepoint-vulnerabilities-china-groups-exploiting

https://thehackernews.com/2025/07/microsoft-links-ongoing-sharepoint.html

https://thehackernews.com/2025/07/hackers-exploit-sharepoint-zero-day.html

https://thehackernews.com/2025/07/cisa-orders-urgent-patching-after.html

https://hackread.com/microsoft-chinese-state-hackers-exploit-sharepoint-flaws/

https://go.theregister.com/feed/www.theregister.com/2025/07/22/microsoft_sharepoint_2016_patch/

https://www.security.com/threat-intelligence/toolshell-zero-day-sharepoint-cve-2025-53770

https://www.infosecurity-magazine.com/news/microsoft-compromising-sharepoint/

https://www.darkreading.com/remote-workforce/microsoft-rushes-emergency-fix-exploited-sharepoint-toolshell-flaw

https://therecord.media/microsoft-sharepoint-zero-day-vulnerability-exploited-globally

https://krebsonsecurity.com/2025/07/microsoft-fix-targets-attacks-on-sharepoint-zero-day/

https://hackread.com/microsoft-hackers-exploit-sharepoint-flaws-patch-now/

https://arstechnica.com/security/2025/07/sharepoint-vulnerability-with-9-8-severity-rating-is-under-exploit-across-the-globe/

https://www.bleepingcomputer.com/news/microsoft/microsoft-sharepoint-zero-day-exploited-in-rce-attacks-no-patch-available/

https://thehackernews.com/2025/07/microsoft-releases-urgent-patch-for.html

https://thehackernews.com/2025/07/critical-microsoft-sharepoint-flaw.html

https://go.theregister.com/feed/www.theregister.com/2025/07/21/infosec_in_brief/

https://research.eye.security/sharepoint-under-siege/

https://www.tenable.com/blog/cve-2025-53770-frequently-asked-questions-about-zero-day-sharepoint-vulnerability-exploitation

https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2025-53771

Details

Source: Mitre, NVD

Published: 2025-07-20

Updated: 2025-07-31

Named Vulnerability: ToolShell

Risk Information

CVSS v2

Base Score: 7.5

Vector: CVSS2#AV:N/AC:L/Au:S/C:C/I:P/A:N

Severity: High

CVSS v3

Base Score: 6.5

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Severity: Medium

EPSS

EPSS: 0.11504

Vulnerability Watch

Tenable Research has classified this CVE under the following Vulnerability Watch classification, which includes active and historical (inactive) classifications. You can learn more about these classifications on our blog.

Vulnerability of Concern