EUVD-2026-56416
GHSA-r293-pwww-9gh8
Severity by source
AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Network-delivered XSS requires an authenticated low-privilege account and active victim interaction; C:H and I:H reflect session token theft and spoofing capability; no availability impact.
Primary rating from Vendor (microsoft).
CVSS VectorNVD
Lifecycle Timeline
5DescriptionNVD
Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Exchange Server allows an authorized attacker to perform spoofing over a network.
AnalysisAI
Cross-site scripting in Microsoft Exchange Server 2016 and 2019 enables authenticated low-privilege users to inject malicious scripts rendered within Exchange web interfaces, allowing spoofing of higher-privileged users over the network. Affected builds span Exchange 2016 CU23, Exchange 2019 CU14 and CU15, and Exchange Server Subscription Edition RTM. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires the attacker to hold a valid low-privilege authenticated account within the target Exchange organization, as confirmed by the CVSS PR:L metric - anonymous or unauthenticated external access is insufficient. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 score of 7.3 reflects a High-severity finding with a network attack vector (AV:N), low complexity (AC:L), a low-privilege authentication requirement (PR:L), and required victim interaction (UI:R). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Organizations should apply the vendor-released patch by upgrading to the following fixed builds as published in MSRC and ENISA EUVD-2026-56416: Exchange 2016 CU23 to version 15.01.2507.072 or later, Exchange 2019 CU14 to version 15.02.1544.044 or later, Exchange 2019 CU15 to version 15.02.1748.049 or later, and Exchange Server Subscription Edition to version 15.02.2562.046 or later. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, inventory your Exchange Server deployment to identify systems running Exchange 2016 CU23, 2019 CU14/CU15, or Subscription Edition RTM. …
Sign in for detailed remediation steps and compensating controls.
Threat intelligence, references, and detailed analysis are available after sign-in.
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Same weakness CWE-79 – Cross-site Scripting (XSS)
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External POC / Exploit Code
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