CVE-2002-0639

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 33.7%, top 3% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Elevated
9.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 18%CVSS: 9.8Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Integer overflow in sshd in OpenSSH 2.9.9 through 3.3 allows remote attackers to execute arbitrary code during challenge response authentication (ChallengeResponseAuthentication) when OpenSSH is using SKEY or BSD_AUTH authentication.

CVSS v3
9.8
EG Score
9.8(medium)
EPSS
96.9%
KEV
Not listed

Published

July 3, 2002

Last Modified

June 16, 2026

Advisory Details (5)

Auto-updated Jun 23, 2026
No patch confirmed yet. Sources: cert.
cert

VU#369347 - OpenSSH vulnerabilities in challenge response handling

http://www.kb.cert.org/vuls/id/369347
generic

Debian -- The Universal Operating System

http://www.debian.org/security/2002/dsa-134
generic

'How to reproduce OpenSSH Overflow.' - MARC

http://marc.info/?l=bugtraq&m=102521542826833&w=2
generic

'Revised OpenSSH Security Advisory (adv.iss)' - MARC

http://marc.info/?l=bugtraq&m=102514631524575&w=2
generic

'OpenSSH Security Advisory (adv.iss)' - MARC

http://marc.info/?l=bugtraq&m=102514371522793&w=2

Frequently asked(5)

What is CVE-2002-0639?
CVE-2002-0639 is a critical vulnerability published on July 3, 2002. Integer overflow in sshd in OpenSSH 2.9.9 through 3.3 allows remote attackers to execute arbitrary code during challenge response authentication (ChallengeResponseAuthentication) when OpenSSH is using SKEY or BSD_AUTH authentication.
When was CVE-2002-0639 disclosed?
CVE-2002-0639 was first published in the National Vulnerability Database on July 3, 2002, with the most recent update on June 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2002-0639 actively exploited?
CVE-2002-0639 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 96.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2002-0639?
CVE-2002-0639 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2002-0639?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2002-0639, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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