CVE-2001-0830: 6tunnel 0.08 and earlier does not properly close sockets that were initiated by a client, which allows remote

Q: How do I fix CVE-2001-0830?

6tunnel: upgrade to newer than 0.08. Exact commands for each OS are on this page.

Q: Is CVE-2001-0830 being exploited?

CVE-2001-0830 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2001-0830 affect?

CVE-2001-0830 affects 6tunnel. Severity is high (CVSS 7.5). 6tunnel 0.08 and earlier does not properly close sockets that were initiated by a client, which allows remote attackers to cause a denial of service (resource exhaustion) by repeatedly connecting to and disconnecting from the server.

Q: How urgent is CVE-2001-0830?

Priority 59/100. High severity; EPSS top 7%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action

This week

HIGH 7.5REMOTEUPGRADE

CVE-2001-0830 is a high-severity flaw (CVSS 7.5) affecting 6tunnel. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

6tunnel 0.08 and earlier does not properly close sockets that were initiated by a client, which allows remote attackers to cause a denial of service (resource exhaustion) by repeatedly connecting to and disconnecting from the server.

Why this priority

High severity
EPSS top 7%: very likely to be exploited
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	5.7% (top 7%)
CISA exploited list	No
Weakness	CWE-772
Published	2001-12-06
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: 6tunnel project

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

Am I affected?

Timeline

2001-12-06 05:00 UTCPublished CVE record published
2026-06-16 21:55 UTCUpdated Record last modified

6tunnel project 6tunnel UPGRADE

Affected: <= 0.08

Fixed in: newer than 0.08

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy 6tunnel || rpm -q 6tunnel || 6tunnel --version

2. UPGRADE to newer than 0.08 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade 6tunnel

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade 6tunnel

Note

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

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: 6Tunnel 0.6/0.7/0.8 - Connection Close State Denial of Service

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-2001-0830?

6tunnel: upgrade to newer than 0.08. Exact commands for each OS are on this page.

Is CVE-2001-0830 being exploited?

CVE-2001-0830 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-2001-0830 affect?

CVE-2001-0830 affects 6tunnel. Severity is high (CVSS 7.5). 6tunnel 0.08 and earlier does not properly close sockets that were initiated by a client, which allows remote attackers to cause a denial of service (resource exhaustion) by repeatedly connecting to and disconnecting from the server.

How urgent is CVE-2001-0830?

Priority 59/100. High severity; EPSS top 7%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action

References

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