CVE-2002-1359: Multiple SSH2 servers and clients do not properly handle large packets or large fields, which may allow remote

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HIGH 10.0MITIGATEDOWNGRADEDOWNGRADE

CVE-2002-1359 is a high-severity flaw (CVSS 10.0) affecting ios, ssh client, securenetterm. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Multiple SSH2 servers and clients do not properly handle large packets or large fields, which may allow remote attackers to cause a denial of service or possibly execute arbitrary code via buffer overflow attacks, as demonstrated by the SSHredder SSH protocol test suite.

Why this priority

Critical severity
EPSS top 1%: very likely to be exploited
Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	10.0 (High)
EPSS exploit chance	80.2% (top 1%)
CISA exploited list	No
Weakness	CWE-20
Published	2002-12-23
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: cisco · fissh · intersoft · netcomposite · pragma systems · putty

Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2002-12-23 05:00 UTCPublished CVE record published
2026-06-16 21:59 UTCUpdated Record last modified

cisco ios MITIGATE

Affected: 12.0s · 12.0st · 12.1e · 12.1ea · 12.1t · 12.2 · 12.2s · 12.2t

Fixed in: no fixed release known

Safe to downgrade to: a release before 12.0s

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

fissh ssh client DOWNGRADE

Affected: 1.0a_for_windows

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.0a_for_windows

1. Check installed version

apt-cache policy ssh-client || rpm -q ssh-client || ssh-client --version

2. No fixed release: DOWNGRADE to a release before 1.0a_for_windows (Debian / Ubuntu)

apt-cache madison ssh-client sudo apt install ssh-client=<VERSION_BEFORE_1.0a_for_windows> sudo apt-mark hold ssh-client

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list ssh-client sudo dnf downgrade ssh-client-<VERSION_BEFORE_1.0a_for_windows> sudo dnf versionlock add ssh-client

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

intersoft securenetterm DOWNGRADE

Affected: 5.4.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 5.4.1

1. Check installed version

apt-cache policy securenetterm || rpm -q securenetterm || securenetterm --version

2. No fixed release: DOWNGRADE to a release before 5.4.1 (Debian / Ubuntu)

apt-cache madison securenetterm sudo apt install securenetterm=<VERSION_BEFORE_5.4.1> sudo apt-mark hold securenetterm

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list securenetterm sudo dnf downgrade securenetterm-<VERSION_BEFORE_5.4.1> sudo dnf versionlock add securenetterm

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

netcomposite shellguard ssh DOWNGRADE

Affected: 3.4.6

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.4.6

1. Check installed version

apt-cache policy shellguard-ssh || rpm -q shellguard-ssh || shellguard-ssh --version

2. No fixed release: DOWNGRADE to a release before 3.4.6 (Debian / Ubuntu)

apt-cache madison shellguard-ssh sudo apt install shellguard-ssh=<VERSION_BEFORE_3.4.6> sudo apt-mark hold shellguard-ssh

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list shellguard-ssh sudo dnf downgrade shellguard-ssh-<VERSION_BEFORE_3.4.6> sudo dnf versionlock add shellguard-ssh

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

pragma systems secureshell DOWNGRADE

Affected: 2.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.0

1. Check installed version

apt-cache policy secureshell || rpm -q secureshell || secureshell --version

2. No fixed release: DOWNGRADE to a release before 2.0 (Debian / Ubuntu)

apt-cache madison secureshell sudo apt install secureshell=<VERSION_BEFORE_2.0> sudo apt-mark hold secureshell

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list secureshell sudo dnf downgrade secureshell-<VERSION_BEFORE_2.0> sudo dnf versionlock add secureshell

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

putty putty DOWNGRADE

Affected: 0.48 · 0.49 · 0.53

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.48

1. Check installed version

apt-cache policy putty || rpm -q putty || putty --version

2. No fixed release: DOWNGRADE to a release before 0.48 (Debian / Ubuntu)

apt-cache madison putty sudo apt install putty=<VERSION_BEFORE_0.48> sudo apt-mark hold putty

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list putty sudo dnf downgrade putty-<VERSION_BEFORE_0.48> sudo dnf versionlock add putty

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Exploit-DB: PuTTy.exe 0.53 - Remote Buffer Overflow (Metasploit)
Exploit-DB: PuTTy.exe 0.53 - Validation Remote Buffer Overflow (Metasploit)
Metasploit: PuTTY Buffer Overflow

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2002-1359?

ios: mitigate or apply the listed mitigation; ssh client: downgrade or apply the listed mitigation; securenetterm: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2002-1359 being exploited?

CVE-2002-1359 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2002-1359 affect?

CVE-2002-1359 affects ios, ssh client, securenetterm. Severity is high (CVSS 10.0). Multiple SSH2 servers and clients do not properly handle large packets or large fields, which may allow remote attackers to cause a denial of service or possibly execute arbitrary code via buffer overflow attacks, as demonstrated by the SSH

How urgent is CVE-2002-1359?

Priority 65/100. Critical severity; EPSS top 1%: very likely to be exploited; Public exploit reference

Software pages

iOS vulnerabilities · Cisco vulnerabilities · PuTTY vulnerabilities

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References

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