Microsoft SharePoint Server improper authentication spoofing vulnerability (ToolShell component)
CVE-2025-49706 is an improper authentication flaw in on-premises Microsoft Office SharePoint / SharePoint Server that allows network-based spoofing and authentication bypass. The provided content identifies the vulnerable logic in the PostAuthenticateRequestHandler method of Microsoft.SharePoint.dll. A logic bug allows a request to bypass authentication checks when the HTTP Referrer header is set to one of the SharePoint sign-out paths, specifically /_layouts/SignOut.aspx, /_layouts/14/SignOut.aspx, or /_layouts/15/SignOut.aspx, using case-insensitive comparison. The flaw was abused as part of the publicly named ToolShell exploit chain, typically in conjunction with CVE-2025-49704, by sending crafted requests to the SharePoint ToolPane endpoint (for example /_layouts/15/ToolPane.aspx). The original July 2025 fix was later reported to be bypassable via path manipulation, leading Microsoft to issue a related follow-on fix under CVE-2025-53771.
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Impact
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Exploits
No valid public exploits. Mallory filtered out 2 candidates as fakes, detection scripts, or README-only repos.
All candidate exploits were filtered out by Mallory's validation.
Affected products & vendors
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Recent activity
164 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A publicly disclosed SharePoint vulnerability used by Storm-2603 for initial access into unpatched on-premises SharePoint servers.
A SharePoint vulnerability referenced as part of the 2025 ToolShell exploitation campaign in which chained SharePoint flaws were used to target customers.
A previously disclosed Microsoft SharePoint vulnerability (not further described in the content) referenced as related to later variant zero-days that were heavily exploited in 2025.
Microsoft SharePoint Server vulnerability added to CISA KEV due to active exploitation (details not provided in excerpt).
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Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
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Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.