Apache Kylin CVE-2026-108743

Exploitation requires the Apache Kylin service to be directly reachable over the network - the vendor explicitly states impact is concentrated on Kylin instances exposed to the public internet, and that in-house (network-isolated) deployments are mostly not impacted. The injectable surface is the Spark job launch path, so an attacker must be able to supply or influence input that flows into the OS command that launches Spark jobs (affected versions 4.0.4 through 5.0.4). Key limiting factors: public exposure of Kylin is uncommon per the vendor, isolated internal clusters are largely unaffected, and the privilege/authentication level required to submit or configure a job is not disclosed (technical details are held in the ASF private security process), so network segmentation and access controls materially reduce realistic risk.

No CVSS vector, EPSS score, KEV entry, or public POC was provided for this issue, so quantitative exploitation signals are entirely absent and the assessment rests on the vendor advisory and CWE-78 (OS Command Injection) context. The vendor (Apache/ASF) rates this 'moderate' and explicitly scopes real-world risk: impact is concentrated on Kylin services directly exposed to the public network, which the advisory states is uncommon, while in-house deployments are mostly not affected. This is the decisive signal - a command-injection flaw in the Spark job launch path is technically high-impact (OS command execution in the Kylin service context), but the vendor's own deployment guidance indicates the realistic blast radius is limited by how rarely Kylin is internet-facing. There is no evidence of active exploitation (not in CISA KEV) and no public exploit identified at time of analysis, so this reads as a genuine-but-conditional priority rather than a widespread emergency: patch promptly where Kylin is network-exposed, lower urgency for isolated internal clusters. Note the conflict to verify: the technical class (OS command execution) would normally warrant HIGH/CRITICAL, yet the assigned severity is 'moderate' precisely because of the exposure and likely privilege prerequisites - confirm the exact access needed with the ASF private security process, as full technical details are withheld per the KYLIN-6106 ticket.

An attacker who can reach an internet-exposed Apache Kylin instance (versions 4.0.4-5.0.4) submits or manipulates input that is passed into the Spark job launch command, injecting shell metacharacters that cause arbitrary OS commands to run on the Kylin host. Because full technical details remain in the private ASF security process and no public exploit has been identified, weaponization details are unconfirmed, but the vulnerability class permits code execution in the context of the Kylin service account. In-house, network-isolated deployments are largely out of reach for this scenario.