CVE-2018-16738: tinc 1.0.30 through 1.0.34 has a broken authentication protocol, although there is a partial mitigation

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LOW 3.7REMOTEWATCHLISTUPGRADEMITIGATEDOWNGRADE

CVE-2018-16738 is a low-severity flaw (CVSS 3.7) affecting tinc, debian linux, starwind virtual san. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

tinc 1.0.30 through 1.0.34 has a broken authentication protocol, although there is a partial mitigation. This is fixed in 1.1.

Why this priority

Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	3.7 (Low)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	1.4% (top 28%)
CISA exploited list	No
Weakness	CWE-287
Published	2018-10-10
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: debian · starwindsoftware · tinc-vpn

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

Am I affected?

Timeline

2018-10-10 21:29 UTCPublished CVE record published
2026-06-17 01:44 UTCUpdated Record last modified

tinc-vpn tinc UPGRADE

Affected: >= 1.0.30 and <= 1.0.34

Fixed in: newer than 1.0.34

Safe to downgrade to: a release before 1.0.30

1. Check installed version

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

2. UPGRADE to newer than 1.0.34 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade tinc

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade tinc

Note

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

3. If no update is available yet, DOWNGRADE to a release before 1.0.30 (Debian / Ubuntu)

apt-cache madison tinc sudo apt install tinc=<VERSION_BEFORE_1.0.30> sudo apt-mark hold tinc

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list tinc sudo dnf downgrade tinc-<VERSION_BEFORE_1.0.30> sudo dnf versionlock add tinc

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.

debian debian linux MITIGATE

Affected: 9.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 9.0

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.

starwindsoftware starwind virtual san DOWNGRADE

Affected: v8 build12533 · v8 build12658

Fixed in: no fixed release known

Safe to downgrade to: a release before v8

1. Check installed version

apt-cache policy starwind-virtual-san || rpm -q starwind-virtual-san || starwind-virtual-san --version

2. No fixed release: DOWNGRADE to a release before v8 (Debian / Ubuntu)

apt-cache madison starwind-virtual-san sudo apt install starwind-virtual-san=<VERSION_BEFORE_v8> sudo apt-mark hold starwind-virtual-san

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

dnf --showduplicates list starwind-virtual-san sudo dnf downgrade starwind-virtual-san-<VERSION_BEFORE_v8> sudo dnf versionlock add starwind-virtual-san

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-2018-16738?

tinc: upgrade to newer than 1.0.34; debian linux: mitigate or apply the listed mitigation; starwind virtual san: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2018-16738 being exploited?

CVE-2018-16738 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-2018-16738 affect?

CVE-2018-16738 affects tinc, debian linux, starwind virtual san. Severity is low (CVSS 3.7). tinc 1.0.30 through 1.0.34 has a broken authentication protocol, although there is a partial mitigation. This is fixed in 1.1.

How urgent is CVE-2018-16738?

Priority 41/100. Remotely exploitable, no login, no user action; On your watchlist

Software pages

Debian vulnerabilities

Related CVEs

CVE-2018-16758 MEDIUM 5.9 UPGRADE MITIGATE Missing message authentication in the meta-protocol in Tinc VPN version 1.0.34 and earlier allows a man-in-the
CVE-2018-16737 MEDIUM 5.3 UPGRADE DOWNGRADE tinc before 1.0.30 has a broken authentication protocol, without even a partial mitigation.

References

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