CVE-2021-26855
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CVSS Score
V3.1EPSS Score
v2025.03.14There is a 94.4% chance that this vulnerability will be exploited in the wild within the next 30 days.
Attack Vector Metrics
Impact Metrics
Description
No description available
Available Exploits
Microsoft Exchange Server SSRF Vulnerability
This vulnerability is part of an attack chain that could allow remote code execution on Microsoft Exchange Server. The initial attack requires the ability to make an untrusted connection to Exchange server port 443. Other portions of the chain can be triggered if an attacker already has access or can convince an administrator to open a malicious file. Be aware his CVE ID is unique from CVE-2021-26412, CVE-2021-26854, CVE-2021-26857, CVE-2021-26858, CVE-2021-27065, and CVE-2021-27078.
References:
- https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2021-26855
- https://proxylogon.com/#timeline
- https://web.archive.org/web/20210306113850/https://raw.githubusercontent.com/microsoft/CSS-Exchange/main/Security/http-vuln-cve2021-26855.nse
- https://gist.github.com/testanull/324546bffab2fe4916d0f9d1f03ffa09
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26855
Related News
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Known Exploited Vulnerability
This vulnerability is actively being exploited in the wild
Remediation Status
Due Date
Added to KEV
Required Action
Apply updates per vendor instructions.
Affected Product
Ransomware Risk
GitHub Security Advisories
Community-driven vulnerability intelligence from GitHub
Advisory Details
CVSS Scoring
CVSS Score
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
Advisory provided by GitHub Security Advisory Database. Published: May 24, 2022, Modified: May 24, 2022
Social Media Intelligence
Real-time discussions and threat intelligence from social platforms
Microsoft SharePoint Server RCE Vulnerability CVE-2025-53770 Greetings, Here's a brief update on a vulnerability in on-premise sharepoint servers, CVE-2025-53770, released today by Microsoft. This vulnerability allows attackers to remotely execute arbitrary code on our servers without any authentication. It is a great danger for organizations using on-premise sharepoint as it …