Apache Polaris: No protection on `write.metadata.path` (CVE-2026-42812)
Published Last modified Sources: EUVD, CVE.org, OSV
What is affected, what to do
In Apache Iceberg, the table's metadata files are control files: they tell readers which data files belong to the table and which table version to read. `write.metadata.path` is an optional table property that tells Polaris where to write those metadata files. For a table already registered in a Polaris-managed catalog, changing only that property through an `ALTER TABLE`-style settings change (not a row-level `INSERT`, `SELECT`, `UPDATE`, or `DELETE`) bypasses the commit-time branch that is supposed to revalidate storage locations.
Update Apache Polaris to version 1.4.1.
- Affected
- Apache Polaris
lt *..1.4.1
- Apache Polaris
- Fixed in
- Apache Polaris
1.4.1
- Apache Polaris
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Metrics
9.9
Priority
XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.
Source: NVD, CVSS v3
9.9
CVSS v3
Severity Critical on the scale from 0 to 10.
Source: EUVD, CVE.org, OSV
0.4 %
EPSS score
Low — model estimates < 1% exploitation likelihood.
Source: FIRST EPSS, percentile 30.3
Show all metrics
- Severity
- Critical
Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 73.76 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- no public PoC known
XIEM Effective CVSS
XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.
Read in glossary- 9.9 Methodology
CVSS v3
CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.
Read in glossary- 9.9
CVSS v4
CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.
Read in glossary- 9.4
EPSS score
The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.
Read in glossary- 0.4 %
- Low — model estimates < 1% exploitation likelihood.
EPSS percentile
The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.
Read in glossary- 30.3
- Elevated — this CVE ranks above at least 10% of all CVEs scored today.
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- —
- Published
- CISA assessment (SSVC)
- Exploitation: none known · not automatable · Technical impact: total
- Source: CISA Vulnrichment, as of 4 May 2026
CWE
CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.
Read in glossary- CWE-20, CWE-284, CWE-732, CWE-863
Detection rules
No NEOSEC detection rule is available for this vulnerability yet.
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
Description
In Apache Iceberg, the table's metadata files are control files: they tell readers which data files belong to the table and which table version to read. `write.metadata.path` is an optional table property that tells Polaris where to write those metadata files. For a table already registered in a Polaris-managed catalog, changing only that property through an `ALTER TABLE`-style settings change (not a row-level `INSERT`, `SELECT`, `UPDATE`, or `DELETE`) bypasses the commit-time branch that is supposed to revalidate storage locations. The full persisted / credential-vending variant requires the affected catalog to have `polaris.config.allow.unstructured.table.location=true`, with `allowedLocations` broad enough to include the attacker-chosen target. `allowedLocations` is the admin-configured allowlist of storage paths that the catalog is allowed to use. Public project materials suggest that this flag is a real supported compatibility / layout mode, not just a contrived lab-only prerequisite. In that configuration, a user who can change table settings can cause Apache Polaris itself to write new table metadata to an attacker-chosen reachable storage location before the intended location-validation branch runs. If the later concrete-path validation also accepts that location, Polaris persists the resulting metadata path into stored table state. Later table-load and credential APIs can then return temporary cloud-storage credentials for the same location without revalidating it. In plain terms, Polaris can later hand out temporary storage access for the same attacker-chosen area. That attacker-chosen area does not need to be limited to the poisoned table's own files. If it is a broader storage prefix, another table's prefix, or, depending on configuration or provider behavior, even a bucket/container root, the resulting disclosure or corruption scope can extend to any data and metadata Polaris can reach there. The practical consequences are therefore similar to the staged-create credential-vending issue already discussed: data and metadata reachable in that storage scope can be exposed and, if write-capable credentials are later issued, modified, corrupted, or removed. Even before that later credential step, Polaris itself performs the metadata write to the unchecked location. So the core issue is not only later credential vending. The primary defect is that Polaris skips its intended location checks before performing a security- sensitive metadata write when only `write.metadata.path` changes. When `polaris.config.allow.unstructured.table.location=false`, current code review suggests the later `updateTableLike(...)` validation usually rejects out-of-tree metadata locations before the unsafe path is persisted. That may reduce the persisted / credential-vending variant, but it does not prevent the underlying defect: Polaris still skips the intended pre-write location check when only `write.metadata.path` changes.
Source: ENISA EUVD, NVD (NIST), CVE.org (MITRE), cvelistv5, OSV (Open Source Vulnerabilities)
Affected products
The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.
| Affected versions | Fixed in | ||
|---|---|---|---|
| Apache Software Foundation | Apache Polaris |
|
|
| apache | polaris |
|
|
| maven | org.apache.polaris:polaris-runtime-service |
|
|
Vendors and products
Weakness classes (CWE)
CWE-20Improper Input Validation
Class
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
Entry at MITRE CWE-20CWE-284Improper Access Control
Pillar
The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.
Entry at MITRE CWE-284CWE-732Incorrect Permission Assignment for Critical Resource
Class
The product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors.
Entry at MITRE CWE-732CWE-863Incorrect Authorization
Class
The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
Entry at MITRE CWE-863
References & sources
- NVD (NIST)vuln/detail/CVE-2026-42812advisory
- github.comapache/polaris/commit/d6bbcc386e61d08ba5df1f820d0724816d84427bweb
- github.comapache/polarispackage
- lists.apache.orgthread/wxd2wj3p0smvrk84msv317wg5tp3jtw9web, Vendor advisory, Mailing list, Vendor advisory
- openwall.comlists/oss-security/2026/05/02/13web, Mailing list, Third-party advisory
- github.comapache/polaris/commit/1cdac7b78c0aa6cc6cad4da10a442ae262d1aae3web
Changes to this CVE
Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).
One NVD translation into another language is hidden.
Linked advisories
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<a href="https://intel.neosec.eu/en/cve/CVE-2026-42812"><img src="https://intel.neosec.eu/badge/cve/CVE-2026-42812.svg?lang=en" alt="CVE-2026-42812 – NEOSEC Intel" height="20"></a>