CVE-2020-27209: The ECDSA operation of the micro-ecc library 1.0 is vulnerable to simple power analysis attacks which allows a

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HIGH 7.5REMOTEDOWNGRADE

CVE-2020-27209 is a high-severity flaw (CVSS 7.5) affecting micro-ecc. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The ECDSA operation of the micro-ecc library 1.0 is vulnerable to simple power analysis attacks which allows an adversary to extract the private ECC key.

Why this priority

High severity
Remotely exploitable, no login, no user action

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

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.5% (top 25%)
CISA exploited list	No
Published	2021-05-20
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: micro-ecc project

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

Am I affected?

Timeline

2021-05-20 21:15 UTCPublished CVE record published
2026-06-17 03:08 UTCUpdated Record last modified

micro-ecc project micro-ecc DOWNGRADE

Affected: 1.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.0

1. Check installed version

apt-cache policy micro-ecc || rpm -q micro-ecc || micro-ecc --version

2. No fixed release: DOWNGRADE to a release before 1.0 (Debian / Ubuntu)

apt-cache madison micro-ecc sudo apt install micro-ecc=<VERSION_BEFORE_1.0> sudo apt-mark hold micro-ecc

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

dnf --showduplicates list micro-ecc sudo dnf downgrade micro-ecc-<VERSION_BEFORE_1.0> sudo dnf versionlock add micro-ecc

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-2020-27209?

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

Is CVE-2020-27209 being exploited?

CVE-2020-27209 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-2020-27209 affect?

CVE-2020-27209 affects micro-ecc. Severity is high (CVSS 7.5). The ECDSA operation of the micro-ecc library 1.0 is vulnerable to simple power analysis attacks which allows an adversary to extract the private ECC key.

How urgent is CVE-2020-27209?

Priority 50/100. High severity; Remotely exploitable, no login, no user action

References

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