How severe is CVE-2001-0999?

CVE-2001-0999 has a CVSS 2.0 base score of 7.5, rated high severity.

Is CVE-2001-0999 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 12% (96th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2001-0999?

CVE-2001-0999 affects Microsoft Outlook Express. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2001-0999?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2001-0999 published?

CVE-2001-0999 was published on 2001-09-12 and last updated on 2026-06-16.

CVE-2001-0999

CVE-2001-0999 is a high-severity vulnerability in Microsoft Outlook Express with a CVSS 2.0 base score of 7.5. Its EPSS exploit-prediction score of 12% places it in the 96th percentile, indicating an elevated likelihood of exploitation.

Key facts

Severity: High (CVSS 2.0 base score 7.5)
EPSS exploit prediction: 12% (96th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Microsoft Outlook Express
Published: 2001-09-12
Last modified: 2026-06-16

Description

Outlook Express 6.00 allows remote attackers to execute arbitrary script by embedding SCRIPT tags in a message whose MIME content type is text/plain, contrary to the expected behavior that text/plain messages will not run script.

Frequently asked questions

What is CVE-2001-0999?: Outlook Express 6.00 allows remote attackers to execute arbitrary script by embedding SCRIPT tags in a message whose MIME content type is text/plain, contrary to the expected behavior that text/plain messages will not run script.
How severe is CVE-2001-0999?: CVE-2001-0999 has a CVSS 2.0 base score of 7.5, rated high severity.
Is CVE-2001-0999 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 12% (96th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2001-0999?: CVE-2001-0999 affects Microsoft Outlook Express. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2001-0999?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2001-0999 published?: CVE-2001-0999 was published on 2001-09-12 and last updated on 2026-06-16.

References

Affected products (1)

cpe:2.3:a:microsoft:outlook_express:6.0:*:*:*:*:*:*:*

More vulnerabilities in Microsoft Outlook Express

CVE-2004-0380 — Critical (CVSS 10.0): The MHTML protocol handler in Microsoft Outlook Express 5.5 SP2 through Outlook Express 6 SP1 allows remote attackers…
CVE-1999-0967 — Critical (CVSS 10.0): Buffer overflow in the HTML library used by Internet Explorer, Outlook Express, and Windows Explorer via the res: local…
CVE-2010-3147 — Critical (CVSS 9.3): Untrusted search path vulnerability in wab.exe 6.00.2900.5512 in Windows Address Book in Microsoft Windows XP SP2 and…
CVE-2010-0816 — Critical (CVSS 9.3): Integer overflow in inetcomm.dll in Microsoft Outlook Express 5.5 SP2, 6, and 6 SP1; Windows Live Mail on Windows XP…
CVE-2007-3897 — Critical (CVSS 9.3): Heap-based buffer overflow in Microsoft Outlook Express 6 and earlier, and Windows Mail for Vista, allows remote…
CVE-2007-4040 — High (CVSS 8.8): Argument injection vulnerability involving Microsoft Outlook and Outlook Express, when certain URIs are registered,…

All CVEs affecting Microsoft Outlook Express →