CVE-2009-0557
CVE-2009-0557 is a security flaw in Microsoft Office, part of Microsoft Office. Attackers can run their own code on Microsoft Office. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 8 Jun 2022.[1]
Microsoft Office is in things households have, such as phones, computers, browsers and everyday apps, so the fix matters at home as much as at work. Microsoft has published a fix or advice.
Description
CISA calls it an object record corruption in Microsoft Office. In its words: “Microsoft Office contains an object record corruption vulnerability that allows remote attackers to execute code via a crafted Excel file with a malformed record object.”[1]
The CVE record adds: “Excel in Microsoft Office 2000 SP3, Office XP SP3, Office 2003 SP3, and Office 2004 and 2008 for Mac; Excel in 2007 Microsoft Office System SP1 and SP2; Open XML File Format Converter for Mac; Microsoft Office Excel Viewer 2003 SP3; Microsoft Office Excel Viewer; and Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats SP1 and SP2 allow remote attackers to execute arbitrary code via a crafted Excel file with a malformed record object, aka "Object Record Corruption Vulnerability."”[2]
The underlying weakness is code injection (CWE-94), in MITRE’s list of common software weaknesses.
It scores 7.8 out of 10 on the Common Vulnerability Scoring System, which rates it high, scored by NVD using CVSS 3.1.[2]
Affected versions
NVD’s record doesn’t list version ranges for it; Microsoft’s advisory has them[3]. CISA names the product as Microsoft Office.
Every device with Microsoft Office needs the update.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 8 Jun 2022, 4,746 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 22 Jun 2022 to fix it.[1]
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 53%. That’s in the top 2% of the flaws it scores.[4]
CISA assesses it as not automatable: each attack takes some work.
CISA doesn’t say who was attacked, or how.
Fix
Microsoft has published a fix or advice.[3] CISA’s required action: “Apply updates per vendor instructions.”[1]
- Update Microsoft Office now.On Windows: Settings, Windows Update, Check for updates, then restart. Office updates come the same way, or from any Office app: File, Account, Update Options. Then turn on automatic updates, so the next fix arrives on its own.
- If there’s no update, stop using it.CISA’s advice when a flaw being used in attacks has no fix is to stop using the product until it does.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 7.8.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at 53%.[4] |
See also
Other Microsoft Office flaws
- CVE-2009-0238: remote code execution ·
- CVE-2026-21514: word reliance on untrusted inputs in a security decision ·
- CVE-2026-21509: security feature bypass ·
- CVE-2009-0556: powerPoint code injection ·
- CVE-2007-0671: excel remote code execution ·
- CVE-2023-23397: outlook privilege escalation ·
Other Microsoft flaws
- CVE-2026-96951, Microsoft Windows: command injection ·
- CVE-2026-65660, Microsoft SharePoint: code injection ·
- CVE-2026-85880, Microsoft Windows: heap-based buffer overflow ·
- CVE-2026-81963, Microsoft Windows: link following ·
- CVE-2019-1068, Microsoft SQL Server: remote code execution ·
Other code injection flaws
- CVE-2026-0322, Palo Alto Networks PAN-OS: code injection ·
- CVE-2026-60004, Gitea: code injection ·
- CVE-2026-72530, TrueConf Server: code injection ·
- CVE-2025-62593, Ray-Project Ray: code injection ·
- CVE-2026-9198, IBM Langflow: code injection ·
Added the same day
- CVE-2019-7195, QNAP Photo Station: path traversal ·
- CVE-2019-7194, QNAP Photo Station: path traversal ·
- CVE-2019-7193, QNAP QTS: improper input validation ·
- CVE-2019-7192, QNAP Photo Station: improper access control ·
- CVE-2019-5825, Chrome and other Chromium browsers: out-of-bounds write ·
Every Microsoft flaw on CISA’s list · Everything added in June 2022
References
- ^ Cybersecurity and Infrastructure Security Agency. “Microsoft Office Object Record Corruption Vulnerability”. Known Exploited Vulnerabilities Catalog, added 8 Jun 2022.
- ^ National Institute of Standards and Technology. “CVE-2009-0557 Detail”. National Vulnerability Database, published 10 Jun 2009.
- ^ Microsoft. Advisories and fixes: docs.microsoft.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.528, percentile 99.0, 31 Oct 2026.
- CVE Program. “CVE-2009-0557”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.