CVE-2020-27985: Security Onion v2 prior to 2.3.10 has an incorrect sudo configuration, which allows the administrative user to

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HIGH 7.8UPGRADE

CVE-2020-27985 is a high-severity flaw (CVSS 7.8) affecting security onion. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Security Onion v2 prior to 2.3.10 has an incorrect sudo configuration, which allows the administrative user to obtain root access without using the sudo password by editing and executing /home/<user>/SecurityOnion/setup/so-setup.

Why this priority

High severity
Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	7.8 (High)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.5% (top 55%)
CISA exploited list	No
Weakness	CWE-306
Published	2020-11-23
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: securityonionsolutions

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

Am I affected?

Timeline

2020-11-23 14:15 UTCPublished CVE record published
2026-06-17 03:09 UTCUpdated Record last modified

securityonionsolutions security onion UPGRADE

Affected: >= 2.0.0 and < 2.3.10

Fixed in: 2.3.10

Safe to downgrade to: a release before 2.0.0

1. Check installed version

apt-cache policy security-onion || rpm -q security-onion || security-onion --version

2. UPGRADE to 2.3.10 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade security-onion

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade security-onion

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 2.0.0 (Debian / Ubuntu)

apt-cache madison security-onion sudo apt install security-onion=<VERSION_BEFORE_2.0.0> sudo apt-mark hold security-onion

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

dnf --showduplicates list security-onion sudo dnf downgrade security-onion-<VERSION_BEFORE_2.0.0> sudo dnf versionlock add security-onion

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-2020-27985?

security onion: upgrade to 2.3.10. Exact commands for each OS are on this page.

Is CVE-2020-27985 being exploited?

CVE-2020-27985 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-2020-27985 affect?

CVE-2020-27985 affects security onion. Severity is high (CVSS 7.8). Security Onion v2 prior to 2.3.10 has an incorrect sudo configuration, which allows the administrative user to obtain root access without using the sudo password by editing and executing /home/<user>/SecurityOnion/setup/so-setup.

How urgent is CVE-2020-27985?

Priority 44/100. High severity; Public exploit reference

Software pages

Sudo vulnerabilities

References

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