How severe is CVE-2001-0543?

CVE-2001-0543 has a CVSS 2.0 base score of 5.0, rated medium severity.

Is CVE-2001-0543 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 21% (97th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2001-0543?

CVE-2001-0543 primarily affects Microsoft Exchange Server. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2001-0543?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2001-0543 published?

CVE-2001-0543 was published on 2001-09-20 and last updated on 2026-06-16.

CVE-2001-0543

CVE-2001-0543 is a medium-severity vulnerability in Microsoft Exchange Server with a CVSS 2.0 base score of 5.0. Its EPSS exploit-prediction score of 21% places it in the 97th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-401.

Key facts

Severity: Medium (CVSS 2.0 base score 5.0)
EPSS exploit prediction: 21% (97th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-401
Affected product: Microsoft Exchange Server
Published: 2001-09-20
Last modified: 2026-06-16

Description

Memory leak in NNTP service in Windows NT 4.0 and Windows 2000 allows remote attackers to cause a denial of service (memory exhaustion) via a large number of malformed posts.

Frequently asked questions

What is CVE-2001-0543?: Memory leak in NNTP service in Windows NT 4.0 and Windows 2000 allows remote attackers to cause a denial of service (memory exhaustion) via a large number of malformed posts.
How severe is CVE-2001-0543?: CVE-2001-0543 has a CVSS 2.0 base score of 5.0, rated medium severity.
Is CVE-2001-0543 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 21% (97th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2001-0543?: CVE-2001-0543 primarily affects Microsoft Exchange Server. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2001-0543?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2001-0543 published?: CVE-2001-0543 was published on 2001-09-20 and last updated on 2026-06-16.

References

Affected products (3)

cpe:2.3:a:microsoft:exchange_server:2000:-:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_2000:*:*:*:*:*:*:*:*
cpe:2.3:o:microsoft:windows_nt:4.0:*:*:*:*:*:*:*

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