CVE-2020-1226Network attack vector

Code execution via PivotField object use-after-free

Published Jun 9, 2020 · Updated Aug 4, 2024

Use-after-free in Microsoft Excel allows remote attackers to execute code when a user opens a crafted XLS file containing malformed HTML/XML. The PivotField HTML/XML parser frees an object without clearing its pointer, then bypasses reuse checks and dereferences the stale object. Exploitation requires user interaction with the malicious workbook; successful heap grooming runs attacker-controlled code in the user's Excel process.

CVSS severity8.8
High
EPSS probability17.08%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Use-after-free in Microsoft Excel allows remote attackers to execute code when a user opens a crafted XLS file containing malformed HTML/XML. The PivotField HTML/XML parser frees an object without clearing its pointer, then bypasses reuse checks and dereferences the stale object. Exploitation requires user interaction with the malicious workbook; successful heap grooming runs attacker-controlled code in the user's Excel process.

The record

CVE
CVE-2020-1226
Published
Jun 9, 2020
Updated
Aug 4, 2024
Vendor
Microsoft
Product
Microsoft Office
Classifications
CWE-416, T1204.002, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 9, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2016 for Mac
  2. Affected versionversion=2019 for 32-bit editions
  3. Affected versionversion=2019 for 64-bit editions
  4. Affected versionversion=2019 for Mac

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Microsoft Officeversion=2016 for Mac; version=2019 for 32-bit editions; version=2019 for 64-bit editions; version=2019 for Mac
Microsoft · Microsoft Excelversion=2010 Service Pack 2 (32-bit editions); version=2010 Service Pack 2 (64-bit editions); version=2013 RT Service Pack 1; version=2013 Service Pack 1 (32-bit editions); version=2013 Service Pack 1 (64-bit editions); version=2016 (32-bit edition); version=2016 (64-bit edition)
Microsoft · Microsoft 365 Apps for enterpriseversion=unspecified

Published CVSS scores

9.3NIST NVDAV:N/AC:M/Au:N/C:C/I:C/A:C
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
8.8Cisco TalosCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-416Use After Free
T1204.002User Execution: Malicious File
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo