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Response snapshot Oct 27, 2026, 00:51 UTC

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VulnerabilityCVE-2026-42811

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...

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.

Published Updated

At a glance

Exploited
Not known
Severity
9.4 Critical (CVSS 4.0)
Chance of exploitation
0.4% in the next 30 days
Sources
2 independent sources

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-42811 (opens a new tab)

What happened

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.

Continue reading

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:

- list another table's object prefix;

- read another table's metadata control file (Iceberg metadata JSON);

- create and delete an object under another table's object prefix;

- 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.

Scores and how they were measured

CVSS base severity

9.4

Version 4.0As of

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

0.4%

Scored Percentile 37.2%

Model and measurement source (opens a new tab)

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    NVD CVE-2026-42811 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  2. Primary source

    Vendor advisory (via NVD references) (opens a new tab)

    The vendor advisory referenced by the CVE record, for affected versions and fixes.

    Published Date not suppliedChecked

  3. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  4. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  5. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  6. Primary source

    FIRST measured EPSS score (opens a new tab)

    Measured EPSS probability and percentile for CVE-2026-42811, scored 2026-10-26. This is a model estimate, not proof of exposure.

    Published Checked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 26). 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... (CVE-2026-42811). https://kevwire.com/record/CVE-2026-42811

MLA

"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... (CVE-2026-42811)." KEVWire, 26 Oct. 2026, kevwire.com/record/CVE-2026-42811.

Chicago

KEVWire. "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... (CVE-2026-42811)." Last modified October 26, 2026. https://kevwire.com/record/CVE-2026-42811.

Evidence summary (plain text)

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... (May 4, 2026).
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:


- list another table's object prefix;

- read another table's metadata control file (Iceberg metadata JSON);

- create and delete an object under another table's object prefix;

- 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.
CVSS 9.4 (version 4.0; evidence as of Oct 26, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-42811).
EPSS 0.4% for the following 30 days, scored Oct 26, 2026 (https://api.first.org/data/v1/epss?cve=CVE-2026-42811&date=2026-10-26).
Sources:
NVD CVE-2026-42811: https://nvd.nist.gov/vuln/detail/CVE-2026-42811
Vendor advisory (via NVD references): https://lists.apache.org/thread/hovn5hmkj9wj7v9cd8sn67svg03klgvg
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-26T19:01:15.495Z&lastModEndDate=2026-10-26T20:30:55.133Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-26T18:27:03.991Z&lastModEndDate=2026-10-26T20:00:55.952Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-26T17:56:10.576Z&lastModEndDate=2026-10-26T19:25:57.867Z&resultsPerPage=500&startIndex=0
FIRST measured EPSS score: https://api.first.org/data/v1/epss?cve=CVE-2026-42811&date=2026-10-26
Record ID: CVE-2026-42811.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 26, 2026, 19:40 UTC. Ingestion is not an independent editorial investigation.

NVD status: Analyzed. Publication in the NVD is not evidence of exploitation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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