CVE-2002-0666: IPSEC implementations including (1) FreeS/WAN and (2) KAME do not properly calculate the length of authenticat

Routine

MEDIUM 5.0DOWNGRADEMITIGATEMITIGATE

CVE-2002-0666 is a medium-severity flaw (CVSS 5.0) affecting frees wan, mac os x, mac os x server. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

IPSEC implementations including (1) FreeS/WAN and (2) KAME do not properly calculate the length of authentication data, which allows remote attackers to cause a denial of service (kernel panic) via spoofed, short Encapsulating Security Payload (ESP) packets, which result in integer signedness errors.

Why this priority

No elevated risk signals yet

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

Risk facts

CVSS score	5.0 (Medium)
EPSS exploit chance	2.5% (top 15%)
CISA exploited list	No
Published	2002-11-04
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: apple · freebsd · frees wan · global technology associates · netbsd

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

Am I affected?

Timeline

2002-11-04 05:00 UTCPublished CVE record published
2026-06-16 21:57 UTCUpdated Record last modified

frees wan frees wan DOWNGRADE

Affected: 1.9 · 1.9.1 · 1.9.2 · 1.9.3 · 1.9.4 · 1.9.5 · 1.9.6

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.9

1. Check installed version

apt-cache policy frees-wan || rpm -q frees-wan || frees-wan --version

2. No fixed release: DOWNGRADE to a release before 1.9 (Debian / Ubuntu)

apt-cache madison frees-wan sudo apt install frees-wan=<VERSION_BEFORE_1.9> sudo apt-mark hold frees-wan

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

dnf --showduplicates list frees-wan sudo dnf downgrade frees-wan-<VERSION_BEFORE_1.9> sudo dnf versionlock add frees-wan

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.

apple mac os x MITIGATE

Affected: 10.2

Fixed in: no fixed release known

Safe to downgrade to: a release before 10.2

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.

apple mac os x server MITIGATE

Affected: 10.2

Fixed in: no fixed release known

Safe to downgrade to: a release before 10.2

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.

freebsd freebsd MITIGATE

Affected: 4.6 · 4.6 release · 4.6 stable

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.6

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.

netbsd netbsd MITIGATE

Affected: 1.5 · 1.5.1 · 1.5.2 · 1.5.3 · 1.6 beta

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.5

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.

global technology associates gnat box firmware MITIGATE

Affected: 3.1 · 3.2 · 3.3

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.1

Firmware

Install the latest firmware from the vendor advisory; if none, apply the vendor workaround.

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-2002-0666?

frees wan: downgrade or apply the listed mitigation; mac os x: mitigate or apply the listed mitigation; mac os x server: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2002-0666 being exploited?

CVE-2002-0666 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-2002-0666 affect?

CVE-2002-0666 affects frees wan, mac os x, mac os x server. Severity is medium (CVSS 5.0). IPSEC implementations including (1) FreeS/WAN and (2) KAME do not properly calculate the length of authentication data, which allows remote attackers to cause a denial of service (kernel panic) via spoofed, short Encapsulating Security Payl

How urgent is CVE-2002-0666?

Priority 39/100. No elevated risk signals yet.

Related CVEs

CVE-2005-3671 HIGH 7.8 DOWNGRADE DOWNGRADE The Internet Key Exchange version 1 (IKEv1) implementation in Openswan 2 (openswan-2) before 2.4.4, and freesw
CVE-2004-0590 HIGH 10.0 DOWNGRADE DOWNGRADE FreeS/WAN 1.x and 2.x, and other related products including superfreeswan 1.x, openswan 1.x before 1.0.6, open

References

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