CVE-2026-87976 is a high severity path traversal flaw in Apache NiFi Registry, scored 8.1. Apache NiFi Registry 2.12.0, per the record text. Check your installed version against the affected list below, then patch or restrict access until you can. The record does not flag it as exploited.
What's affected
- Apache NiFi Registry 0.4.0 through 2.11.0.
Severity in the record: High (8.1), vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H. Weakness: CWE-22.
Fix: Apache NiFi Registry 2.12.0, per the record text.
How to check if you're exposed
- Read the version from the NiFi Registry web UI footer or from the jar names:
ls lib | grep nifi-registry. - Check whether the file persistence provider is in use for extension bundles.
Run these on every host, image and build that could carry the component. Dependency files in repositories and base images in registries are easy to miss.
What to do now
- Confirm the version of every affected system using the checks above.
- Read the vendor advisory linked in Sources and note the fixed version for your release line.
- Schedule the update, starting with systems that face untrusted networks or hold the most sensitive data.
- In the meantime: review who holds write and delete rights on buckets.
- Record the change, then recheck the version to confirm it took effect.
Why it matters
Group, artifact and version coordinates from an uploaded NAR manifest are used as filesystem path components. Parent-directory names were not rejected, and the containment check compared a path that had not been normalized. That is CWE-22 path traversal. An authenticated user allowed to write and delete bundles in a bucket can cause file operations outside the persistence directory. In 2.12.0 parent-directory coordinates are rejected and the normalized path must stay a strict child of the storage root.
The record's KEV flag is false, so this post makes no claim that the flaw is exploited in the wild. That can change, so recheck the CISA catalog from time to time.
Libraries like this often arrive as transitive dependencies, so the version in your lockfile may not be one you chose. Safeguard's free in-browser dependency scan can show whether the package is in a project, and reachability analysis helps separate code paths that call the weak function from those that never do.
The vector string in the record is a compact summary of how the flaw is reached and what it costs. AV is the attack vector (network, adjacent or local), PR is the privilege the attacker needs, and the C, I and A letters give the impact on confidentiality, integrity and availability. Read it against your own network layout rather than relying on the score alone.
After you patch
Patching is not the end of the job. Recheck the version on each system, because an upgrade that failed or rolled back looks the same as a success until someone looks. Keep the advisory link with your change record so the next reviewer can see why the update happened.
If you cannot patch soon, write down the reason, the compensating control you chose and a date to revisit. Exceptions without a date tend to become permanent.
Quick check
Which version fixes it?
Apache NiFi Registry 2.12.0, according to the record's description.
Sources
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Apache mailing list: advisory thread
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Safeguard Gold: CVE-2026-87976
Last reviewed: 18 October 2026.
