CVE-2018-18409: A stack-based buffer over-read exists in setbit() at iptree.h of TCPFLOW 1.5.0, due to received incorrect valu

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MEDIUM 5.5WATCHLISTDOWNGRADEMITIGATEMITIGATE

CVE-2018-18409 is a medium-severity flaw (CVSS 5.5) affecting tcpflow, fedora, ubuntu linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A stack-based buffer over-read exists in setbit() at iptree.h of TCPFLOW 1.5.0, due to received incorrect values causing incorrect computation, leading to denial of service during an address_histogram call or a get_histogram call.

Why this priority

Public exploit reference
On your watchlist

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

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	1.3% (top 30%)
CISA exploited list	No
Weakness	CWE-125
Published	2018-10-17
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: canonical · digitalcorpora · fedoraproject

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2018-10-17 04:29 UTCPublished CVE record published
2026-06-17 01:47 UTCUpdated Record last modified

digitalcorpora tcpflow DOWNGRADE

Affected: 1.5.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.5.0

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 1.5.0 (Debian / Ubuntu)

apt-cache madison tcpflow sudo apt install tcpflow=<VERSION_BEFORE_1.5.0> sudo apt-mark hold tcpflow

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

dnf --showduplicates list tcpflow sudo dnf downgrade tcpflow-<VERSION_BEFORE_1.5.0> sudo dnf versionlock add tcpflow

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.

fedoraproject fedora MITIGATE

Affected: 28 · 29

Fixed in: no fixed release known

Safe to downgrade to: a release before 28

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.

canonical ubuntu linux MITIGATE

Affected: 16.04 · 18.04 · 18.10

Fixed in: no fixed release known

Safe to downgrade to: a release before 16.04

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.

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-2018-18409?

tcpflow: downgrade or apply the listed mitigation; fedora: mitigate or apply the listed mitigation; ubuntu linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2018-18409 being exploited?

CVE-2018-18409 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-2018-18409 affect?

CVE-2018-18409 affects tcpflow, fedora, ubuntu linux. Severity is medium (CVSS 5.5). A stack-based buffer over-read exists in setbit() at iptree.h of TCPFLOW 1.5.0, due to received incorrect values causing incorrect computation, leading to denial of service during an address_histogram call or a get_histogram call.

How urgent is CVE-2018-18409?

Priority 47/100. Public exploit reference; On your watchlist

Software pages

Ubuntu vulnerabilities

Related CVEs

CVE-2026-25061 HIGH 7.5 UPGRADE MITIGATE tcpflow is a TCP/IP packet demultiplexer
CVE-2003-0671 HIGH 7.2 DOWNGRADE Format string vulnerability in tcpflow, when used in a setuid context, allows local users to execute arbitrary

References

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