CVE-2002-0601: ISS RealSecure Network Sensor 5.x through 6.5 allows remote attackers to cause a denial of service (crash) via

Routine

MEDIUM 5.0DOWNGRADE

CVE-2002-0601 is a medium-severity flaw (CVSS 5.0) affecting realsecure network sensor. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

ISS RealSecure Network Sensor 5.x through 6.5 allows remote attackers to cause a denial of service (crash) via malformed DHCP packets that cause RealSecure to dereference a null pointer.

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 16%)
CISA exploited list	No
Published	2002-06-18
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: information security systems

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

Am I affected?

Timeline

2002-06-18 04:00 UTCPublished CVE record published
2026-06-16 21:57 UTCUpdated Record last modified

information security systems realsecure network sensor DOWNGRADE

Affected: 5.0_xpu_3.4 · 5.5.1_xpu_3.4 · 5.5.2_xpu_3.4 · 5.5_xpu_3.4 · 6.0_xpu_3.4 · 6.5

Fixed in: no fixed release known

Safe to downgrade to: a release before 5.0_xpu_3.4

1. Check installed version

apt-cache policy realsecure-network-sensor || rpm -q realsecure-network-sensor || realsecure-network-sensor --version

2. No fixed release: DOWNGRADE to a release before 5.0_xpu_3.4 (Debian / Ubuntu)

apt-cache madison realsecure-network-sensor sudo apt install realsecure-network-sensor=<VERSION_BEFORE_5.0_xpu_3.4> sudo apt-mark hold realsecure-network-sensor

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

dnf --showduplicates list realsecure-network-sensor sudo dnf downgrade realsecure-network-sensor-<VERSION_BEFORE_5.0_xpu_3.4> sudo dnf versionlock add realsecure-network-sensor

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.

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-2002-0601?

realsecure network sensor: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2002-0601 being exploited?

CVE-2002-0601 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-2002-0601 affect?

CVE-2002-0601 affects realsecure network sensor. Severity is medium (CVSS 5.0). ISS RealSecure Network Sensor 5.x through 6.5 allows remote attackers to cause a denial of service (crash) via malformed DHCP packets that cause RealSecure to dereference a null pointer.

How urgent is CVE-2002-0601?

Priority 39/100. No elevated risk signals yet.

Related CVEs

CVE-2004-0362 HIGH 7.5 DOWNGRADE DOWNGRADE Multiple stack-based buffer overflows in the ICQ parsing routines of the ISS Protocol Analysis Module (PAM) co
CVE-2001-0669 HIGH 7.5 MITIGATE MITIGATE Various Intrusion Detection Systems (IDS) including (1) Cisco Secure Intrusion Detection System, (2) Cisco Cat

References

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