CVE-2009-0238 — Microsoft Office Remote Code Execution

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

CISA required action CISA

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

US federal deadline: Apr 28, 2026 — passed 170 day(s) ago

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

1. Identify exposed assets running the affected vendor/product/version combinations (Microsoft Excel, Microsoft Excel Viewer, Microsoft Office…).
2. Treat as emergency remediation: the CVE is in CISA KEV (confirmed exploitation).
3. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
4. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
5. Exploitation requires user interaction: tighten email/web filtering and warn affected users.
6. EPSS ahead of 99% of scored CVEs: prioritize it in the patch queue.
7. Search available logs for exploit probes matching the vulnerability class (injection), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-94 · Code Injection

Other CVEs with this weakness →

CISA KEV details CISA

CISA lists a CVE once it has evidence of exploitation against real targets.

CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a reference date.

EPSS over time FIRST

Oct 12, 2026 → Oct 14, 2026 · 3 reading(s) · max 43.21%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

• Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
• Look for parameters with command/query metacharacters and unexpected child processes of the service.
• Hunt retroactively in logs from before Apr 14, 2026 (KEV listing): exploitation may have started earlier.

Timeline

What happened to this CVE, newest first.

• 2026
• SSVC assessment updated
  Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
• Record published
  Oct 13, 2026
• Affected products added · microsoft/excel, microsoft/excel viewer, microsoft/office, microsoft/office compatibility pack, microsoft/office excel v
  Oct 13, 2026 · NIST National Vulnerability Database
• CVSS changed · 8.8
  Oct 13, 2026 · NIST National Vulnerability Database
• Source status changed · → Analyzed
  Oct 13, 2026 · NIST National Vulnerability Database
• Added to CISA KEV (detected)
  Oct 13, 2026 · CISA Known Exploited Vulnerabilities
• Record created in this database
  Oct 13, 2026 · CISA Known Exploited Vulnerabilities
• Added to CISA KEV catalog
  Apr 13, 2026 · CISA
• 2009
• CVE published
  Feb 25, 2009 · microsoft

Source activity

Repeated readings are counted rather than listed.

• 2× References added · Oct 13, 2026 – Oct 13, 2026
• 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

14 on the record

• docs.microsoft.com/en-us/security-updates/securitybulletins/2009/ms09-009
  Vendor Advisory, vendor-advisory, x_refsource_MS, NIST National Vulnerability Database
• www.microsoft.com/technet/security/advisory/968272.mspx
  Vendor Advisory, x_refsource_CONFIRM, NIST National Vulnerability Database
• www.cisa.gov/known-exploited-vulnerabilities-catalog
  US Government Resource, NIST National Vulnerability Database
• www.us-cert.gov/cas/techalerts/TA09-104A.html
  US Government Resource, third-party-advisory, x_refsource_CERT, NIST National Vulnerability Database
• blogs.zdnet.com/security/
  Broken Link, x_refsource_MISC, NIST National Vulnerability Database
• www.symantec.com/business/security_response/writeup.jsp
  Broken Link, x_refsource_MISC, NIST National Vulnerability Database
• oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A5968
  Broken Link, vdb-entry, signature, x_refsource_OVAL, NIST National Vulnerability Database
• www.vupen.com/english/advisories/2009/1023
  Broken Link, vdb-entry, x_refsource_VUPEN, NIST National Vulnerability Database
• exchange.xforce.ibmcloud.com/vulnerabilities/48875
  Third Party Advisory, vdb-entry, x_refsource_XF, NIST National Vulnerability Database
• github.com/advisories/GHSA-qw7j-w352-g8m7
  GitHub Security Advisories
• isc.sans.org/diary.html
  Press/Media Coverage, x_refsource_MISC, NIST National Vulnerability Database
• www.securityfocus.com/bid/33870
  Broken Link, vdb-entry, x_refsource_BID, NIST National Vulnerability Database
• nvd.nist.gov/vuln/detail/CVE-2009-0238
  GitHub Security Advisories
• securitytracker.com/id
  Broken Link, vdb-entry, x_refsource_SECTRACK, NIST National Vulnerability Database

Elsewhere on this site

Related CVEs (same products)

• Medium CVE-2026-54988 Microsoft Excel Information Disclosure Vulnerability Jul 14, 2026
• Low CVE-2026-50678 Heap-based Buffer Overflow in Microsoft 365 Apps Jul 14, 2026
• High CVE-2026-50675 Heap-based Buffer Overflow in Microsoft 365 Apps Jul 14, 2026
• High CVE-2026-47293 Microsoft Office Click-To-Run Elevation of Privilege Vulnerability Jun 9, 2026
• High CVE-2026-45649 Office for Android Spoofing Vulnerability Jun 9, 2026
• High CVE-2026-45469 Microsoft Excel Remote Code Execution Vulnerability Jun 9, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

• No fixed version, patch or mitigation documented.
• No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
• No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
• No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2009-0238 is "Microsoft Office Remote Code Execution", rated High. It affects Excel (Microsoft); versions are in the scope table. It is in CISA KEV: there is evidence of real-world exploitation. CVSS 8.8 describes technical severity. EPSS 43.21% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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