This document describes Apache Iceberg's detailed security threat model for maintainers and automated security triage.
It complements the shorter public-facing security model in
site/docs/security.md by making Iceberg's trust
assumptions, security boundaries, and recurring non-security bug classes more
explicit.
Apache Iceberg is often deployed as a library and integration layer inside larger systems that provide their own authentication, authorization, and credential management. Because of that deployment model, many bug classes that look security-relevant in the abstract are not actually security vulnerabilities in Iceberg itself.
This model is intended to answer:
- what Iceberg generally treats as a security vulnerability
- what Iceberg generally treats as correctness, hardening, or deployment work
- which boundaries are primarily owned by Iceberg versus the surrounding catalog, engine, or service
- which issue classes should be downgraded by default by scanners
This model is scoped to the Apache Iceberg project itself:
- the table format implementation
- client libraries
- engine integrations
- catalog-related components shipped in the Iceberg repository
It is not a general threat model for every deployment that embeds Iceberg.
In particular, it does not attempt to define the complete security model for:
- query engines or applications that embed Iceberg
- storage-level authorization enforced outside Iceberg
Iceberg should:
- avoid exposing secrets or delegated credentials to principals that were not already trusted with them
- avoid creating new unauthorized capabilities in Iceberg-owned components or integrations
- avoid violating trust boundaries that Iceberg itself owns, such as leaking signer, auth, or credential-bearing state across catalog or session boundaries in the same process
Iceberg does not aim to be the primary enforcement point for:
- user-to-user authorization inside a query engine
- storage-level authorization
- service-side credential scoping performed by an external catalog
The operator deploys and configures the catalog, metastore, REST service, engine, and storage integration around Iceberg. This role is trusted to choose endpoints, warehouses, and storage integrations, configure credentials, and decide which users may create tables, read tables, or invoke maintenance actions.
The catalog control plane is responsible for resolving tables and supplying metadata, locations, configuration, and delegated credentials to Iceberg. This role may be implemented by a REST catalog server, a metastore-backed catalog, or another catalog implementation. Regardless of how it is implemented, it should not expose secrets to unintended principals or leak credential-bearing state across unintended boundaries.
Iceberg assumes a trusted catalog or metastore, which is outside its primary security boundary.
In REST deployments, part of the catalog control plane is implemented by a server that returns metadata, configuration, and possibly delegated credentials to the client. This server is generally treated as a trusted control-plane component.
In REST deployments, the client-side catalog object consumes server-provided metadata, configuration, and credentials. Where the client and server are meaningfully distinct, client-side bugs in routing, caching, or reuse may still be security-relevant. This is especially true when the Iceberg-owned client implementation leaks credential-bearing state across catalog, session, or principal boundaries it is expected to preserve.
Query engines and applications may expose only a subset of Iceberg capabilities to users. They are responsible for their own user-facing authorization boundaries unless Iceberg explicitly documents otherwise.
This role may already have legitimate power to write or replace table metadata, write or delete files, choose paths under an allowed warehouse or table location, and invoke destructive maintenance operations. If a report only shows a new way to achieve the same effect this role can already cause legitimately, it is usually not a security issue in Iceberg.
The following are generally treated as trusted operator or deployment inputs:
- catalog properties
- endpoint configuration
- warehouse and storage roots
- metastore wiring
- REST catalog server configuration
If a report depends on the attacker controlling those values directly, it is usually not a vulnerability in Iceberg itself.
Iceberg often accepts metadata locations, table properties, namespace properties, and related control-plane information from a catalog or metastore. By default, Iceberg treats those sources as trusted.
This means a malicious catalog supplying incorrect or malicious metadata is usually not an Iceberg vulnerability by itself.
In REST deployments, Iceberg may also accept service endpoints, configuration, and delegated storage access from the REST catalog server. By default, those are treated as trusted control-plane inputs unless Iceberg explicitly documents a stronger guarantee.
This means a malicious REST catalog server sending dangerous endpoints is usually not an Iceberg vulnerability by itself. It also means many client-side credential-selection bugs are often correctness or specification issues rather than security boundary failures.
The major exception is secret exposure. If Iceberg surfaces credentials or secrets to a new audience that was not already trusted with them, that is security-relevant.
Object store permissions are enforced by the storage provider and the credentials the surrounding deployment chooses to hand to Iceberg. Iceberg is not the root authority for bucket- or object-level authorization.
Reports that depend primarily on over-broad IAM or permissive storage ACLs are usually deployment-sensitive rather than product-security issues in Iceberg.
Iceberg integrations may surface data and operations through a query engine or application, but Iceberg is not a complete user-authorization framework for those systems.
The following categories are generally security-relevant in Iceberg when the report is credible and reproducible.
Examples include:
- catalog secrets exposed through a user-visible engine surface
- one catalog's credentials or auth state leaking into another catalog or session
Security issues exist when Iceberg itself is expected to separate catalogs, principals, or sessions and fails to do so.
Examples include:
- process-global signer or auth state crossing catalog instances
- secret-bearing state from one principal reused for another principal within an Iceberg-owned boundary
These categories may still be real bugs worth fixing, but they are not usually security vulnerabilities in Iceberg itself.
Examples:
- wrong byte offsets
- stale or corrupted decoded values
- ambiguous prefix matching
- race conditions or logic bugs that do not create a new trust-boundary violation
Malformed-input crashes, raw runtime exceptions, and memory amplification are usually treated as robustness or hardening work rather than security issues in Iceberg itself.
Reports that require a malicious catalog, metastore, or other external service are usually outside Iceberg's primary security boundary.
If the actor already has a legitimate capability that can cause the same harm, the new path is usually not a security issue. This often applies to writers or maintainers who already control metadata layout, file layout, or destructive maintenance operations.
A scanner targeting Iceberg should treat a finding as higher-confidence only if it plausibly shows one of the following:
- exposure of a secret or delegated credential to a new audience
- creation of a new unauthorized capability in an Iceberg-owned component
- violation of an Iceberg-owned trust boundary rather than a surrounding catalog, engine, service, or operator boundary
A finding should be downgraded or rejected by default if it instead depends primarily on:
- malformed-input robustness or denial-of-service behavior
- a malicious catalog, metastore, or external service
- a principal that already has equivalent power through legitimate write or maintenance capabilities