CVE-2020-0695Network attack vector

Cross-origin spoofing via origin validation failure

Published Feb 11, 2020 · Updated Aug 4, 2024

Origin-validation flaw in Microsoft Office Online Server allows remote attackers to spoof cross-origin communications through crafted web requests. The server accepts cross-origin messages without correctly checking their declared origin, enabling a malicious site or response to be treated as trusted by a browser user. Exploitation requires network access and user interaction with web content; reported impact is limited to confidentiality and integrity effects, with no availability impact described.

CVSS severity5.4
Medium
EPSS probability0.97%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Origin-validation flaw in Microsoft Office Online Server allows remote attackers to spoof cross-origin communications through crafted web requests. The server accepts cross-origin messages without correctly checking their declared origin, enabling a malicious site or response to be treated as trusted by a browser user. Exploitation requires network access and user interaction with web content; reported impact is limited to confidentiality and integrity effects, with no availability impact described.

The record

CVE
CVE-2020-0695
Published
Feb 11, 2020
Updated
Aug 4, 2024
Vendor
Microsoft
Product
Office Online Server
Classifications
CWE-346
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 11, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=unspecified

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Office Online Serverversion=unspecified

Published CVSS scores

5.4NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
5.8NVDAV:N/AC:M/Au:N/C:P/I:P/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-346Origin Validation Error

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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