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

published 2026-05-26 5 mo ago modified 2026-07-24 3 mo ago also EUVD-2026-31846

cvss: 6.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.7%; EPSS 0.7% chance of exploitation in 30 days, percentile 52%
public exploits: 0; none known

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.

Patch / fix

fixed in 1

Apache Software Foundation Apache Flink Kubernetes Operator 1.15.0

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 5 mo ago (2026-06-02)

Exploit prediction

0.67% chance of exploitation in the next 30 days, higher than 52% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CISA ADP	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
NVD	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
CNA	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Affected products

Apache Software Foundation Apache Flink Kubernetes Operator

Classification

Weakness

CWE-552 Files or Directories Accessible to External Parties
CWE-918 Server-Side Request Forgery

References

lists.apache.org /thread/jvxs2kh2o60sl7qkl5nss4r5phzfl4cz
vendor-advisory, mailing-list
openwall.com /lists/oss-security/2026/05/26/6
mailing-list, third-party-advisory

Sources

CVE List CVE-2026-40564
NVD CVE-2026-40564

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary