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CISA KEV · ACTIVELY EXPLOITED
HIGH severity

CVE-2009-0563 — Microsoft

HIGH

CVE-2009-0563 is a high-severity (CVSS 7.8) Out-of-bounds Write vulnerability. It is in CISA's Known Exploited Vulnerabilities catalog (added 2022-06-08) — treat it as actively exploited and patch now. No vendor fix is recorded yet; mitigation options are listed below.

Stack-based buffer overflow in Microsoft Office Word 2002 SP3, 2003 SP3, and 2007 SP1 and SP2; Microsoft Office for Mac 2004 and 2008; Open XML File Format Converter for Mac; Microsoft…

Published
Updated
Affected
4 products
Patched
See advisory
Exploits
2 known
Exploitation data as of Oct 22, 2026 · OSV.dev, NVD, CISA KEV, FIRST.org (EPSS)

Exploitation Status

Actively exploited in the wild

  • Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2022-06-08. Federal agencies were required to remediate by 2022-06-22.
  • 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-2009-0563.

EPSS Exploitation Probability

via FIRST.org ↗
59.6%probability of exploitation in next 30 days
High Risk-3.45%
Lower risk than most CVEs99th percentile — riskier than 99% of all scored CVEsHighest risk
53.5%64.4%75.2%86.0%79.9%59.6%Apr 26Jul 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2009-0563 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

Stack-based buffer overflow in Microsoft Office Word 2002 SP3, 2003 SP3, and 2007 SP1 and SP2; Microsoft Office for Mac 2004 and 2008; Open XML File Format Converter for Mac; Microsoft Office Word Viewer 2003 SP3; Microsoft Office Word Viewer; and Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats SP1 and SP2 allows remote attackers to execute arbitrary code via a Word document with a crafted tag containing an invalid length field, aka "Word Buffer Overflow Vulnerability."

Affected Products

4 products · 12 configurations
Application
officemicrosoft
6 versions
20002003200420072008xp
Application
office compatibility packmicrosoft
1 version
2007
Application
office word viewermicrosoft
1 version
2003
Application
open xml file format convertermicrosoft
all
Exploits & PoCs
2

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Detection & mitigation playbook

Vulnerability
  1. Detect

    Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).

  2. Remediation status

    No fixed release is recorded for CVE-2009-0563 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.

  3. Mitigate without a patch

    Stop feeding it untrusted input: reject or quarantine files and payloads from unverified sources until you can upgrade, restrict accepted formats to the ones you actually need, and run the parsing or decoding step in a least-privileged sandbox or short-lived worker so a crash or corrupted read cannot reach the rest of the process.

Frequently Asked Questions

Stack-based buffer overflow in Microsoft Office Word 2002 SP3, 2003 SP3, and 2007 SP1 and SP2; Microsoft Office for Mac 2004 and 2008; Open XML File Format Converter for Mac; Microsoft Office Word Viewer 2003 SP3; Microsoft Office Word Viewer; and Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats SP1 and SP2 allows remote attackers to execute arbitrary code via a Word document with a crafted tag containing an invalid length field, aka "Word Buffer Overflow Vulnerability."
O3 Security · Impact-Aware SCA

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CVE-2009-0563: Microsoft Memory Corruption (KEV)