CVE-2019-0541 — Excel Viewer
HIGHCVE-2019-0541 is a high-severity (CVSS 8.8) CWE-77 vulnerability in microsoft excel viewer. It is in CISA's Known Exploited Vulnerabilities catalog (added 2021-11-03) — treat it as actively exploited and patch now. No vendor fix is recorded yet; mitigation options are listed below.
A remote code execution vulnerability exists in the way that the MSHTML engine inproperly validates input, aka "MSHTML Engine Remote Code Execution Vulnerability." This affects Microsoft…
Exploitation Status
Actively exploited in the wild
- Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2021-11-03. Federal agencies were required to remediate by 2022-05-03.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2019-0541.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2019-0541 by exploitation likelihood (EPSS) against impact (CVSS). In the shaded patch-first corner (EPSS 50%+, CVSS 7.0+).
Where this sits among everything scored
Of 395,249 CVEs with a current EPSS score, this one falls in the 50–90% band (highlighted). Counts from FIRST.org, log-scaled.
Description
A remote code execution vulnerability exists in the way that the MSHTML engine inproperly validates input, aka "MSHTML Engine Remote Code Execution Vulnerability." This affects Microsoft Office, Microsoft Office Word Viewer, Internet Explorer 9, Internet Explorer 11, Microsoft Excel Viewer, Internet Explorer 10, Office 365 ProPlus.
Affected Products
excel viewermicrosoftinternet explorermicrosoftofficemicrosoftoffice 365 proplusmicrosoftoffice word viewermicrosoftResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Microsoft Windows MSHTML Engine - 'Edit' Remote Code Execution
by Eduardo Braun Prado · Mar 13, 2019
Detection & mitigation playbook
Vendor / applianceDetect
Inventory every microsoft excel viewer deployment and check each version against the affected-products list above.
Remediation status
No patch has shipped for CVE-2019-0541 yet — track the microsoft excel viewer advisory for a fixed release and apply the workarounds below in the meantime.
Mitigate without a patch
Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.
Frequently Asked Questions
Is CVE-2019-0541 being exploited in your environment?
Detect and block the exploit chain at execution, on systems you cannot patch yet.