CVE-2021-34571: Multiple Wireless M-Bus devices by Enbra use Hard-coded Credentials in Security mode 5 without an option to ch

Routine

MEDIUM 6.5DOWNGRADE

CVE-2021-34571 is a medium-severity flaw (CVSS 6.5) affecting ewm. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Multiple Wireless M-Bus devices by Enbra use Hard-coded Credentials in Security mode 5 without an option to change the encryption key. An adversary can learn all information that is available in Enbra EWM.

Why this priority

No elevated risk signals yet

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

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Adjacent network
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 87%)
CISA exploited list	No
Weakness	CWE-798
Published	2021-09-16
Last modified	2026-06-17

Publisher (CNA): CERT VDE · Vendor: enbra

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

Am I affected?

Timeline

2021-09-16 13:15 UTCPublished CVE record published
2026-06-17 03:56 UTCUpdated Record last modified

enbra ewm DOWNGRADE

Affected: 1.7.29

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.7.29

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 1.7.29 (Debian / Ubuntu)

apt-cache madison ewm sudo apt install ewm=<VERSION_BEFORE_1.7.29> sudo apt-mark hold ewm

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

dnf --showduplicates list ewm sudo dnf downgrade ewm-<VERSION_BEFORE_1.7.29> sudo dnf versionlock add ewm

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-2021-34571?

ewm: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-34571 being exploited?

CVE-2021-34571 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-2021-34571 affect?

CVE-2021-34571 affects ewm. Severity is medium (CVSS 6.5). Multiple Wireless M-Bus devices by Enbra use Hard-coded Credentials in Security mode 5 without an option to change the encryption key. An adversary can learn all information that is available in Enbra EWM.

How urgent is CVE-2021-34571?

Priority 26/100. No elevated risk signals yet.

Related CVEs

CVE-2021-34573 MEDIUM 6.2 DOWNGRADE In Enbra EWM in Version 1.7.29 together with several tested wireless M-Bus Sensors the events backflow and "no
CVE-2021-34572 MEDIUM 6.5 DOWNGRADE Enbra EWM 1.7.29 does not check for or detect replay attacks sent by wireless M-Bus Security mode 5 devices

References

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