CVE-2002-0083: Off-by-one error in the channel code of OpenSSH 2.0 through 3.0.2 allows local users or remote malicious serve

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CRITICAL 9.8REMOTEWATCHLISTDOWNGRADEDOWNGRADEUPGRADE

CVE-2002-0083 is a critical-severity flaw (CVSS 9.8) affecting immunix, mandrake single network firewall, openssh. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Off-by-one error in the channel code of OpenSSH 2.0 through 3.0.2 allows local users or remote malicious servers to gain privileges.

Why this priority

Critical severity
EPSS top 3%: very likely to be exploited
Public exploit reference
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	14.7% (top 3%)
CISA exploited list	No
Weakness	CWE-193
Published	2002-03-15
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: conectiva · engardelinux · immunix · mandrakesoft · openbsd · openpkg

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

Am I affected?

Timeline

2002-03-15 05:00 UTCPublished CVE record published
2026-06-16 21:56 UTCUpdated Record last modified

immunix immunix DOWNGRADE

Affected: 7.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 7.0

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 7.0 (Debian / Ubuntu)

apt-cache madison immunix sudo apt install immunix=<VERSION_BEFORE_7.0> sudo apt-mark hold immunix

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

dnf --showduplicates list immunix sudo dnf downgrade immunix-<VERSION_BEFORE_7.0> sudo dnf versionlock add immunix

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.

mandrakesoft mandrake single network firewall DOWNGRADE

Affected: 7.2

Fixed in: no fixed release known

Safe to downgrade to: a release before 7.2

1. Check installed version

apt-cache policy mandrake-single-network-firewall || rpm -q mandrake-single-network-firewall || mandrake-single-network-firewall --version

2. No fixed release: DOWNGRADE to a release before 7.2 (Debian / Ubuntu)

apt-cache madison mandrake-single-network-firewall sudo apt install mandrake-single-network-firewall=<VERSION_BEFORE_7.2> sudo apt-mark hold mandrake-single-network-firewall

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

dnf --showduplicates list mandrake-single-network-firewall sudo dnf downgrade mandrake-single-network-firewall-<VERSION_BEFORE_7.2> sudo dnf versionlock add mandrake-single-network-firewall

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.

openbsd openssh UPGRADE

Affected: >= 2.0 and < 3.1

Fixed in: 3.1

Safe to downgrade to: a release before 2.0

1. Check installed version

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

2. UPGRADE to 3.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade openssh

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade openssh

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 2.0 (Debian / Ubuntu)

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

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

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

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.

openpkg openpkg DOWNGRADE

Affected: 1.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.0

1. Check installed version

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

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

apt-cache madison openpkg sudo apt install openpkg=<VERSION_BEFORE_1.0> sudo apt-mark hold openpkg

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

dnf --showduplicates list openpkg sudo dnf downgrade openpkg-<VERSION_BEFORE_1.0> sudo dnf versionlock add openpkg

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.

conectiva linux MITIGATE

Affected: 5.0 · 5.1 · 6.0 · 7.0 · ecommerce · graficas

Fixed in: no fixed release known

Safe to downgrade to: a release before 5.0

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.

engardelinux secure linux MITIGATE

Affected: 1.0.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.0.1

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.

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.

Fedora 46 · rust-agirru · FIXED · 0.2.0-1.fc46 · FEDORA-2026-4d81cb4100 · source

sudo dnf upgrade --advisory=FEDORA-2026-4d81cb4100

Fedora ELN · fuse-sshfs · FIXED · 3.7.6-3.eln159 · FEDORA-2026-bcb7be7c5c · source

sudo dnf upgrade --advisory=FEDORA-2026-bcb7be7c5c

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: OpenSSH 2.x/3.0.1/3.0.2 - Channel Code Off-by-One

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-2002-0083?

immunix: downgrade or apply the listed mitigation; mandrake single network firewall: downgrade or apply the listed mitigation; openssh: upgrade to 3.1. Exact commands for each OS are on this page.

Is CVE-2002-0083 being exploited?

CVE-2002-0083 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-2002-0083 affect?

CVE-2002-0083 affects immunix, mandrake single network firewall, openssh. Severity is critical (CVSS 9.8). Off-by-one error in the channel code of OpenSSH 2.0 through 3.0.2 allows local users or remote malicious servers to gain privileges.

How urgent is CVE-2002-0083?

Priority 73/100. Critical severity; EPSS top 3%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

Software pages

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References

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