CVE-2026-81866: Apache NiFi 2.9.0 through 2.11.0 provide Connector configuration update and verification REST API methods that

Routine

MEDIUM 4.3WATCHLISTUPGRADE

CVE-2026-81866 is a medium-severity flaw (CVSS 4.3) affecting nifi. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Apache NiFi 2.9.0 through 2.11.0 provide Connector configuration update and verification REST API methods that do not enforce authorization checking on Assets and Secrets referenced in proposed configuration. Updating or verifying a Connector configuration step can apply Asset and Secret references, but framework authorization was limited to write privileges on the Connector itself. As a result of the missing authorization, an authenticated user

Why this priority

On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	4.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.6% (top 53%)
CISA exploited list	No
Weakness	CWE-862
Published	2026-09-16
Last modified	2026-09-21

Publisher (CNA): Apache Software Foundation · Vendor: apache

Last updated 2026-09-21 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-09-16 20:17 UTCPublished CVE record published
2026-09-21 13:38 UTCUpdated Record last modified

apache nifi UPGRADE

Affected: >= 2.9.0 and < 2.12.0

Fixed in: 2.12.0

Safe to downgrade to: a release before 2.9.0

1. Check installed version

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

2. UPGRADE to 2.12.0 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade nifi

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 2.9.0 (Debian / Ubuntu)

apt-cache madison nifi sudo apt install nifi=<VERSION_BEFORE_2.9.0> sudo apt-mark hold nifi

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

dnf --showduplicates list nifi sudo dnf downgrade nifi-<VERSION_BEFORE_2.9.0> sudo dnf versionlock add nifi

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-2026-81866?

nifi: upgrade to 2.12.0. Exact commands for each OS are on this page.

Is CVE-2026-81866 being exploited?

CVE-2026-81866 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-2026-81866 affect?

CVE-2026-81866 affects nifi. Severity is medium (CVSS 4.3). Apache NiFi 2.9.0 through 2.11.0 provide Connector configuration update and verification REST API methods that do not enforce authorization checking on Assets and Secrets referenced in proposed configuration. Updating or verifying a Connect

How urgent is CVE-2026-81866?

Priority 32/100. On your watchlist

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References

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