CVE-2019-20918: An issue was discovered in InspIRCd 3 before 3.1.0

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MEDIUM 6.5UPGRADE

CVE-2019-20918 is a medium-severity flaw (CVSS 6.5) affecting inspircd. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue was discovered in InspIRCd 3 before 3.1.0. The silence module contains a use after free vulnerability. This vulnerability can be used for remote crashing of an InspIRCd server by any user able to fully connect to a server.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	1.5% (top 26%)
CISA exploited list	No
Weakness	CWE-416
Published	2020-09-11
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: inspircd

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

Am I affected?

Timeline

2020-09-11 05:15 UTCPublished CVE record published
2026-06-17 02:31 UTCUpdated Record last modified

inspircd inspircd UPGRADE

Affected: >= 3.0 and < 3.1.0

Fixed in: 3.1.0

Safe to downgrade to: a release before 3.0

1. Check installed version

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

2. UPGRADE to 3.1.0 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade inspircd

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 3.0 (Debian / Ubuntu)

apt-cache madison inspircd sudo apt install inspircd=<VERSION_BEFORE_3.0> sudo apt-mark hold inspircd

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

dnf --showduplicates list inspircd sudo dnf downgrade inspircd-<VERSION_BEFORE_3.0> sudo dnf versionlock add inspircd

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-2019-20918?

inspircd: upgrade to 3.1.0. Exact commands for each OS are on this page.

Is CVE-2019-20918 being exploited?

CVE-2019-20918 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-2019-20918 affect?

CVE-2019-20918 affects inspircd. Severity is medium (CVSS 6.5). An issue was discovered in InspIRCd 3 before 3.1.0. The silence module contains a use after free vulnerability. This vulnerability can be used for remote crashing of an InspIRCd server by any user able to fully connect to a server.

How urgent is CVE-2019-20918?

Priority 41/100. No elevated risk signals yet.

Related CVEs

CVE-2021-33586 MEDIUM 4.3 UPGRADE InspIRCd 3.8.0 through 3.9.x before 3.10.0 allows any user (able to connect to the server) to access recently
CVE-2020-25269 MEDIUM 6.5 UPGRADE MITIGATE An issue was discovered in InspIRCd 2 before 2.0.29 and 3 before 3.6.0
CVE-2019-20917 MEDIUM 6.5 UPGRADE MITIGATE An issue was discovered in InspIRCd 2 before 2.0.28 and 3 before 3.3.0
CVE-2016-7142 MEDIUM 5.9 UPGRADE MITIGATE The m_sasl module in InspIRCd before 2.0.23, when used with a service that supports SASL_EXTERNAL authenticati
CVE-2015-8702 HIGH 8.6 MITIGATE UPGRADE The DNS::GetResult function in dns.cpp in InspIRCd before 2.0.19 allows remote DNS servers to cause a denial o

References

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