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.
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (9.9): severity, escalated by confirmed exploitation. This CVE's 9.9 is its impact severity (EG Severity), not escalated.
- EG Severity
- 9.9 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
- EG Likelihood
- 0.4% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-28). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it