Microsoft Exchange 5.5 allows a remote attacker to relay email (i.e.

published 1999-08-06 27y ago modified 2026-06-16 4mo ago also EUVD-1999-0664

cvss: 5.0; version 2.0, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 26.1%; EPSS 26.1% chance of exploitation in 30 days, percentile 98%
public exploits: 0; none known

Microsoft Exchange 5.5 allows a remote attacker to relay email (i.e. spam) using encapsulated SMTP addresses, even if the anti-relaying features are enabled.

Patch / fix

links 1

docs.microsoft.com/en-us/security-updates/securitybulletins/1999/ms99-027 advisory

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Exploit prediction

26.10% chance of exploitation in the next 30 days, higher than 98% of all scored CVEs (FIRST EPSS, 2026-11-14).

CVSS scores

assigned by	version	score	vector
NVD	2.0	5.0	AV:N/AC:L/Au:N/C:N/I:N/A:P

Classification

Technology feeds

Microsoft Exchange rss critical rss

References

docs.microsoft.com /en-us/security-updates/securitybulletins/1999/ms99-027
vendor-advisory, patch
support.microsoft.com /default.aspx?scid=kb%3B%5BLN%5D%3BQ237927
vendor-advisory
ciac.org /ciac/bulletins/j-056.shtml
third-party-advisory, government-resource, broken-link
securityfocus.com /bid/567
vdb-entry, third-party-advisory

Sources

CVE List CVE-1999-0682
NVD CVE-1999-0682

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