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NVD / CVE Program· CNA mitre

CVE-2002-0640: Buffer overflow in sshd in OpenSSH 2.3.1 through 3.3 may allow remote attackers to execute arbitrary code via a large number of responses…

CriticalCVSS 10.0 · v2.0—Proof of concept Fix available

Noroxi assessment

Priority: Plan (action score 48/100)

  • Public proof-of-concept code exists (Exploit-DB); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 28.1% (FIRST EPSS); higher than 98.1% of all records.
  • No special conditions are required; it is repeatable.
  • Fixed version: openssh (Debian:12) 1:3.4.

Add it to your regular patch cycle. Upgrade to openssh (Debian:12) 1:3.4 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Buffer overflow in sshd in OpenSSH 2.3.1 through 3.3 may allow remote attackers to execute arbitrary code via a large number of responses during challenge response authentication when OpenBSD is using PAM modules with interactive keyboard authentication (PAMAuthenticationViaKbdInt).

Published
Jul 3, 2002
Updated
Jun 16, 2026
EPSS
28.1% · 98th percentile
CWE
—

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Action score

48

Plan

Add it to your regular patch cycle.

CVSS
40 / 40 · 10.0 / 10
CISA KEV
0 / 30 · Not listed
EPSS
8 / 30 · 28.1%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Proof of concept exists, no weaponized module
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
openbsdopenssh

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Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • openbsd openssh1.2.2
  • openbsd openssh1.2.3
  • openbsd openssh2.1
  • openbsd openssh2.1.1
  • openbsd openssh2.2
  • openbsd openssh2.3
  • openbsd openssh2.5
  • openbsd openssh2.5.1
+12 more rows
  • openbsd openssh2.5.2
  • openbsd openssh2.9
  • openbsd openssh2.9.9
  • openbsd openssh2.9p1
  • openbsd openssh2.9p2
  • openbsd openssh3.0
  • openbsd openssh3.0.1
  • openbsd openssh3.0.1p1
  • openbsd openssh3.0.2
  • openbsd openssh3.0.2p1
  • openbsd openssh3.0p1
  • openbsd openssh3.1

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12opensshbefore 1:3.41:3.4

Same product

openbsd: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-123158sshd in OpenSSH before 10.6p2 on Linux, when musl libc is used without PAM, lacks a workaround for a password authentication bypass…KEV
    68This week
  • CVE-2023-38408The PKCS#11 feature in ssh-agent in OpenSSH before 9.3p2 has an insufficiently trustworthy search path, leading to remote code execution if…
    63This week
  • CVE-2018-15473OpenSSH through 7.7 is prone to a user enumeration vulnerability due to not delaying bailout for an invalid authenticating user until after…
    60This week

Published before and after this one in the same product

  • ← EarlierCVE-2002-0575Jun 18, 2002 · Buffer overflow in OpenSSH before 2.9.9, and 3.x before 3.2.1, with Kerberos/AFS support and KerberosTgtPassing or AFSTokenPassing enabled…
    32Monitor
  • ← EarlierCVE-2002-0639Jul 3, 2002 · Integer overflow in sshd in OpenSSH 2.9.9 through 3.3 allows remote attackers to execute arbitrary code during challenge response…
    44Plan
  • Later →CVE-2002-0765Aug 12, 2002 · sshd in OpenSSH 3.2.2, when using YP with netgroups and under certain conditions, may allow users to successfully authenticate and log in…
    30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:openssh1:3.4 · Debian:12Package registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Exploit-DB entry ×2

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Exploit-DB entryremote2002-06-24
Exploit-DB entryremote2002-06-24

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. First PoC-9 d
  2. Published
  3. TodayNov 15, 2026+8901 d

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • No special conditions are required; it is repeatable.

If successful

Confidentiality
C · data can be read
Integrity
C · data or configuration can be modified
Availability
C · the service can be disrupted
Attack complexity
Low
Confidentiality impact
C
Integrity impact
C
Availability impact
C

Weakness class (CWE)

—

CVSS vector

AV:N/AC:L/Au:N/C:C/I:C/A:C

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

References

Show all references (17 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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