CVE-2026-42811
CVE-2026-42811 is a Improper Input Validation vulnerability in org.apache.polaris:polaris-core. O3 Security confirms whether CVE-2026-42811 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Apache Polaris: could broaden vended GCS credentials through unescaped identifier content in access-boundary CEL conditions
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
org.apache.polaris:polaris-coreReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
In plain terms, Apache Polaris is supposed to issue short-lived GCS credentials that only work for one table's files, but a crafted namespace or table name can cause those credentials to work across the configured bucket instead.
Apache Polaris builds Google Cloud Storage downscoped credentials by creating a Credential Access Boundary (CAB) with CEL conditions that are intended to restrict access to the requested table's storage path.
The relevant CEL string is built from the bucket name and the table path. That table path is derived from namespace and table identifiers. In current code, that path appears to be inserted into the CEL expression without escaping.
As a result, a namespace or table identifier containing a single quote and other URI-safe CEL fragments can break out of the intended quoted string and change the meaning of the CEL condition.
In private testing against Polaris 1.4.0 on real Google Cloud Storage, it was confirmed that Polaris accepted a crafted identifier and returned delegated GCS credentials whose CEL path restriction had effectively collapsed.
Those delegated credentials could then:
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list another table's object prefix;
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read another table's metadata control file (Iceberg metadata JSON);
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create and delete an object under another table's object prefix;
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and also list, read, create, and delete objects under an unrelated external prefix in the same bucket that was not part of any table path.
That last point is important. The issue is not limited to "another table". In the confirmed setup, once Apache Polaris returned credentials for the crafted table, the path restriction inside the configured bucket was effectively gone.
The practical effect is that temporary credentials for one crafted table can be broader than the table Polaris was asked to authorize, and can become effectively bucket-wide within the configured bucket.
The current GCS testing used a Polaris principal with broad catalog privileges for setup. A separate least-privilege Polaris RBAC variant has not yet been tested on GCS. However, the storage-credential broadening behavior itself has been confirmed on GCS.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.apache.polaris:polaris-core | all versions | 1.4.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.polaris:polaris-core. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update org.apache.polaris:polaris-core to 1.4.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-42811 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-42811 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-42811. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-42811 in your dependencies?
O3 detects CVE-2026-42811 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.