CVE-2020-8806: Electric Coin Company Zcashd before 2.1.1-1 allows attackers to trigger consensus failure and double spending

Q: How do I fix CVE-2020-8806?

zcashd: upgrade to 2.1.1. Exact commands for each OS are on this page.

Q: Is CVE-2020-8806 being exploited?

CVE-2020-8806 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2020-8806 affect?

CVE-2020-8806 affects zcashd. Severity is high (CVSS 7.5). Electric Coin Company Zcashd before 2.1.1-1 allows attackers to trigger consensus failure and double spending. A valid chain could be incorrectly rejected because timestamp requirements on block headers were not properly enforced.

Q: How urgent is CVE-2020-8806?

Priority 47/100. High severity; Remotely exploitable, no login, no user action

This month

HIGH 7.5REMOTEUPGRADE

CVE-2020-8806 is a high-severity flaw (CVSS 7.5) affecting zcashd. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Electric Coin Company Zcashd before 2.1.1-1 allows attackers to trigger consensus failure and double spending. A valid chain could be incorrectly rejected because timestamp requirements on block headers were not properly enforced.

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.0% (top 36%)
CISA exploited list	No
Weakness	CWE-863
Published	2021-02-05
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: electriccoin

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

Am I affected?

Timeline

2021-02-05 14:15 UTCPublished CVE record published
2026-06-17 03:26 UTCUpdated Record last modified

electriccoin zcashd UPGRADE

Affected: < 2.1.1

Fixed in: 2.1.1

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 2.1.1 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade zcashd

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

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-2020-8806?

zcashd: upgrade to 2.1.1. Exact commands for each OS are on this page.

Is CVE-2020-8806 being exploited?

CVE-2020-8806 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-2020-8806 affect?

CVE-2020-8806 affects zcashd. Severity is high (CVSS 7.5). Electric Coin Company Zcashd before 2.1.1-1 allows attackers to trigger consensus failure and double spending. A valid chain could be incorrectly rejected because timestamp requirements on block headers were not properly enforced.

How urgent is CVE-2020-8806?

Priority 47/100. High severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2020-8807 MEDIUM 5.3 UPGRADE In Electric Coin Company Zcashd before 2.1.1-1, the time offset between messages could be leveraged to obtain

References

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