CVE-2009-4737: Stack-based buffer overflow in JustSystems Corporation Ichitaro 13, 2004 through 2009, Viewer 2009 19.0.1.0 an

This month

HIGH 9.3DOWNGRADEDOWNGRADE

CVE-2009-4737 is a high-severity flaw (CVSS 9.3) affecting ichitaro, ichitaro viewer. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Stack-based buffer overflow in JustSystems Corporation Ichitaro 13, 2004 through 2009, Viewer 2009 19.0.1.0 and earlier, and other versions allows context-dependent attackers to execute arbitrary code via a crafted Rich Text File (RTF), related to "pvpara ffooter."

Why this priority

Critical severity

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	9.3 (High)
EPSS exploit chance	3.5% (top 11%)
CISA exploited list	No
Weakness	CWE-119
Published	2010-04-06
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: justsystems

Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2010-04-06 22:30 UTCPublished CVE record published
2026-06-16 23:14 UTCUpdated Record last modified

justsystems ichitaro DOWNGRADE

Affected: 13 · 2004 · 2005 · 2006 · 2007 · 2008 · 2009 · bungei

Fixed in: no fixed release known

Safe to downgrade to: a release before 13

1. Check installed version

apt-cache policy ichitaro || rpm -q ichitaro || ichitaro --version

2. No fixed release: DOWNGRADE to a release before 13 (Debian / Ubuntu)

apt-cache madison ichitaro sudo apt install ichitaro=<VERSION_BEFORE_13> sudo apt-mark hold ichitaro

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list ichitaro sudo dnf downgrade ichitaro-<VERSION_BEFORE_13> sudo dnf versionlock add ichitaro

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

justsystems ichitaro viewer DOWNGRADE

Affected: 19.0.1.0 · 20.0.2.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 19.0.1.0

1. Check installed version

apt-cache policy ichitaro-viewer || rpm -q ichitaro-viewer || ichitaro-viewer --version

2. No fixed release: DOWNGRADE to a release before 19.0.1.0 (Debian / Ubuntu)

apt-cache madison ichitaro-viewer sudo apt install ichitaro-viewer=<VERSION_BEFORE_19.0.1.0> sudo apt-mark hold ichitaro-viewer

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list ichitaro-viewer sudo dnf downgrade ichitaro-viewer-<VERSION_BEFORE_19.0.1.0> sudo dnf versionlock add ichitaro-viewer

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2009-4737?

ichitaro: downgrade or apply the listed mitigation; ichitaro viewer: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2009-4737 being exploited?

CVE-2009-4737 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2009-4737 affect?

CVE-2009-4737 affects ichitaro, ichitaro viewer. Severity is high (CVSS 9.3). Stack-based buffer overflow in JustSystems Corporation Ichitaro 13, 2004 through 2009, Viewer 2009 19.0.1.0 and earlier, and other versions allows context-dependent attackers to execute arbitrary code via a crafted Rich Text File (RTF), rel

How urgent is CVE-2009-4737?

Priority 55/100. Critical severity

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References

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