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CVE-2026-45504 is a high-severity server-side request forgery vulnerability in on-premises Microsoft Exchange Server 2016, Exchange Server 2019, and Exchange Server Subscription Edition. The flaw is rooted in Exchange’s handling of SharePoint/WOPI document-preview URLs in the OneDriveProUtilities code path, including functions referenced as TryTwice and GetWacUrl. Exchange accepts attacker-influenced WOPI metadata, specifically the WebApplicationUrl field, and fails to enforce scheme restrictions before passing the value into request-handling logic. Because non-HTTP schemes such as file:// are not blocked, an authenticated low-privileged attacker can supply a crafted WebApplicationUrl like file:///C:/Windows/win.ini# and exploit fragment handling to neutralize query parameters appended by Exchange. This causes Exchange to issue a FileWebRequest against the local filesystem and return the file contents through Exchange services. In practice, the attack can be initiated via Exchange Web Services using a crafted ReferenceAttachment whose ProviderEndpointUrl points to an attacker-controlled endpoint that returns malicious WOPI data. Although classified as SSRF/elevation of privilege, the practical primitive demonstrated publicly is arbitrary local file read from the Exchange server, which can then support impersonation and further privilege escalation.
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1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos.
Repository contains a single Python exploit script and a short README with usage example. The script targets Microsoft Exchange and implements an authenticated SSRF-to-local-file-read chain for CVE-2026-45504. It accepts target URL, attacker callback IP/port, credentials, password, and an arbitrary target file path. Execution flow: (1) start a local HTTP server to answer Exchange callback requests with crafted XML containing a file:/// URI to the desired local file; (2) authenticate to OWA via /owa/auth.owa and obtain an OWA canary token; (3) use NTLM-authenticated EWS SOAP requests to /ews/exchange.asmx to create a draft message and then attach a malicious ReferenceAttachment using ProviderType OneDrivePro with attacker-controlled ProviderEndpointUrl/AttachLongPathName; (4) call /owa/service.svc?action=GetAttachmentPreview&id=... to trigger preview generation and return the file contents; (5) print the retrieved bytes to stdout. The exploit is operational rather than a mere PoC because it automates the full chain and returns file contents, but it does not provide a generalized framework or customizable post-exploitation payload beyond arbitrary file read.
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A high-severity Microsoft Exchange server-side request forgery vulnerability that can be turned into an arbitrary-file-read issue by abusing attachment preview and WOPI URL handling, including unsafe acceptance of file:// URIs.
A high-severity Microsoft Exchange Server vulnerability in which insufficient validation of attacker-influenced WOPI/WebApplicationUrl values enables SSRF that can be turned into arbitrary local file reads, leading to privilege escalation and broader compromise.
A server-side request forgery vulnerability in Microsoft Exchange Server that allows an authorized attacker to elevate privileges over a network.
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