CVE-2026-40564: Apache Flink Kubernetes Operator: Server-Side Request Forgery and local file access in Kubernetes Operator

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-26 · updated 2026-07-24
Weakness: CWE-552

Description

Files or Directories Accessible to External Parties, Server-Side Request Forgery (SSRF) vulnerability in Apache Flink Kubernetes Operator. The FlinkSessionJob jarURI is currently not validated so that it points to user-owned files or addresses. This lets a user with CR create permissions read files from the operator pod's filesystem and pull content from any backing store reachable through Flink's pluggable filesystem layer and access them through the submitted Flink job. Furthermore for fetching from http/https addresses there is currently no allowlist on the URI scheme, no host check, no IP-range restriction, and no protection against pointing the URI at internal or link-local addresses.This issue affects Apache Flink Kubernetes Operator: from 1.3.0 before 1.15.0. Users are recommended to upgrade to version 1.15.0, which fixes the issue.

Affected products

Apache Software Foundation Apache Flink Kubernetes Operator: from 1.3.0 before 1.15.0 — fixed in 1.15.0

How to fix

Upgrade to a fixed version: Apache Software Foundation Apache Flink Kubernetes Operator 1.15.0. Check the vendor advisory for mitigations.

References

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