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 19% (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 19% 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: 19% (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 19% (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:*:*:*:*:*:*:*

More vulnerabilities in Microsoft Exchange Server

CVE-2007-0213 — Critical (CVSS 10.0): Microsoft Exchange Server 2000 SP3, 2003 SP1 and SP2, and 2007 does not properly decode certain MIME encoded e-mails,…
CVE-2004-0574 — Critical (CVSS 10.0): The Network News Transfer Protocol (NNTP) component of Microsoft Windows NT Server 4.0, Windows 2000 Server, Windows…
CVE-2004-0840 — Critical (CVSS 10.0): The SMTP (Simple Mail Transfer Protocol) component of Microsoft Windows XP 64-bit Edition, Windows Server 2003, Windows…
CVE-1999-0385 — Critical (CVSS 10.0): The LDAP bind function in Exchange 5.5 has a buffer overflow that allows a remote attacker to conduct a denial of…
CVE-2024-21410 — Critical (CVSS 9.8): Microsoft Exchange Server Elevation of Privilege Vulnerability
CVE-2023-21709 — Critical (CVSS 9.8): Microsoft Exchange Server Elevation of Privilege Vulnerability

All CVEs affecting Microsoft Exchange Server →

Other CWE-401 (Missing Release of Memory after Effective Lifetime) vulnerabilities

CVE-2026-46289 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: lib/scatterlist: fix length calculations in…
CVE-2025-39948 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: ice: fix Rx page leak on multi-buffer frames The…
CVE-2025-21954 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: netmem: prevent TX of unreadable skbs Currently…
CVE-2024-57947 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_set_pipapo: fix initial map…
CVE-2024-56779 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: nfsd: fix nfs4_openowner leak when concurrent…
CVE-2024-36911 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: hv_netvsc: Don't free decrypted memory In CoCo…

Browse all CWE-401 (Missing Release of Memory after Effective Lifetime) vulnerabilities →