CVE-2001-1558: Unknown vulnerability in IP defragmenter (frag2) in Snort before 1.8.3 allows attackers to cause a denial of s

Routine

MEDIUM 5.0DOWNGRADE

CVE-2001-1558 is a medium-severity flaw (CVSS 5.0) affecting snort. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Unknown vulnerability in IP defragmenter (frag2) in Snort before 1.8.3 allows attackers to cause a denial of service (crash).

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	1.1% (top 35%)
CISA exploited list	No
Published	2001-12-31
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: snort

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

Am I affected?

Timeline

2001-12-31 05:00 UTCPublished CVE record published
2026-06-16 21:56 UTCUpdated Record last modified

snort snort DOWNGRADE

Affected: 1.8.0 · 1.8.1 · 1.8.2

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.8.0

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 1.8.0 (Debian / Ubuntu)

apt-cache madison snort sudo apt install snort=<VERSION_BEFORE_1.8.0> sudo apt-mark hold snort

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

dnf --showduplicates list snort sudo dnf downgrade snort-<VERSION_BEFORE_1.8.0> sudo dnf versionlock add snort

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-2001-1558?

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

Is CVE-2001-1558 being exploited?

CVE-2001-1558 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-2001-1558 affect?

CVE-2001-1558 affects snort. Severity is medium (CVSS 5.0). Unknown vulnerability in IP defragmenter (frag2) in Snort before 1.8.3 allows attackers to cause a denial of service (crash).

How urgent is CVE-2001-1558?

Priority 34/100. No elevated risk signals yet.

Software pages

Suricata and Snort vulnerabilities

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References

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