CVE-2022-33993: Misinterpretation of special domain name characters in DNRD (aka Domain Name Relay Daemon) 2.20.3 leads to cac

Routine

MEDIUM 5.3REMOTEDOWNGRADE

CVE-2022-33993 is a medium-severity flaw (CVSS 5.3) affecting domain name relay daemon. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Misinterpretation of special domain name characters in DNRD (aka Domain Name Relay Daemon) 2.20.3 leads to cache poisoning because domain names and their associated IP addresses are cached in their misinterpreted form.

Why this priority

Remotely exploitable, no login, no user action

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

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.9% (top 39%)
CISA exploited list	No
Published	2022-08-15
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: domain name relay daemon project

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

Am I affected?

Timeline

2022-08-15 12:15 UTCPublished CVE record published
2026-06-17 04:49 UTCUpdated Record last modified

domain name relay daemon project domain name relay daemon DOWNGRADE

Affected: 2.20.3

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.20.3

1. Check installed version

apt-cache policy domain-name-relay-daemon || rpm -q domain-name-relay-daemon || domain-name-relay-daemon --version

2. No fixed release: DOWNGRADE to a release before 2.20.3 (Debian / Ubuntu)

apt-cache madison domain-name-relay-daemon sudo apt install domain-name-relay-daemon=<VERSION_BEFORE_2.20.3> sudo apt-mark hold domain-name-relay-daemon

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

dnf --showduplicates list domain-name-relay-daemon sudo dnf downgrade domain-name-relay-daemon-<VERSION_BEFORE_2.20.3> sudo dnf versionlock add domain-name-relay-daemon

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-2022-33993?

domain name relay daemon: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2022-33993 being exploited?

CVE-2022-33993 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-2022-33993 affect?

CVE-2022-33993 affects domain name relay daemon. Severity is medium (CVSS 5.3). Misinterpretation of special domain name characters in DNRD (aka Domain Name Relay Daemon) 2.20.3 leads to cache poisoning because domain names and their associated IP addresses are cached in their misinterpreted form.

How urgent is CVE-2022-33993?

Priority 39/100. Remotely exploitable, no login, no user action

Related CVEs

CVE-2022-33992 HIGH 7.5 DOWNGRADE DNRD (aka Domain Name Relay Daemon) 2.20.3 forwards and caches DNS queries with the CD (aka checking disabled)

References

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