External risk intelligence

Fission Environment PodSpec Passthrough Vulnerability

CVE advisorySeverity: CRITICAL (CVSS 9.9)

CVE-2026-50545

The vulnerability affects Kubernetes-native serverless pod specifications. While network-accessible, this is an internal orchestration component typically managed by authorized DevOps teams. Direct public exposure of these specific configuration interfaces is uncommon in standard secure deployments.

Halo Surface Signal: 2 out of 5 — less likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A security flaw was identified in the Fission open-source framework, which is used for deploying functions and applications on Kubernetes. This issue could potentially allow for unauthorized actions within the Kubernetes environment. The primary concern is to confirm if your environment utilizes Fission and if it is exposed to this vulnerability.

Fission framework has a security flaw.
Understand Fission's role in your systems.
Confirm relevance and exposure status.

Attack Path

How an attacker could exploit the issue

An attacker with low privileges could reach the Fission framework by exploiting its passthrough of dangerous fields within pod specifications. This allows them to inject malicious configurations into generated pods, potentially leading to the compromise of both data confidentiality and integrity, as well as the disruption of service availability.

Requires authenticated access.
Triggered by submitting a crafted pod specification.
Risk of data compromise and service disruption.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could allow an authenticated attacker to inject dangerous fields into Kubernetes pods managed by Fission. When supported by the advisory, this could lead to the execution of arbitrary code or the modification of application behavior within the Kubernetes environment.

Kubernetes pod specifications.
Authenticated attacker injects fields.
Compromise of running applications.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability in Fission, a Kubernetes-native serverless framework, likely impacts platform engineering or DevOps teams responsible for Kubernetes infrastructure and application deployments. The first practical step is to identify all Fission deployments, determine their reachability and criticality, and locate the accountable owners before planning remediation.

Platform or DevOps teams own the issue.
Verify Fission deployment exposure and criticality.
Plan phased updates during maintenance windows.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is Fission?

Fission is an open-source framework designed to simplify serverless computing directly on Kubernetes. Developers use it to deploy functions and applications without manually managing the underlying infrastructure. By automating the creation of Kubernetes pods to execute code, it streamlines workflows, but it requires careful configuration of the environment specifications to ensure that the pods are created securely.

What does CWE-269, CWE-284, and CWE-693 mean for CVE-2026-50545?

These codes indicate issues with improper privilege management, access control, and protection mechanisms. In plain terms, CVE-2026-50545 occurs because the system was too trusting; it allowed pod configuration settings to pass through without sufficient validation. This failure allowed users to inject dangerous fields into pod specifications, essentially bypassing security boundaries intended to keep application deployments restricted and safe.

How is this vulnerability triggered?

An attacker triggers this flaw by submitting a crafted pod specification that includes prohibited or dangerous fields. The vulnerability relies on the framework improperly propagating these fields into generated pods. It is important to note that simply running Fission does not trigger the bug; the attacker must be able to interact with the specification interface with low-level privileges to inject the malicious configuration.

Is my Fission deployment at risk?

According to Halo Surface Signal, this vulnerability is unlikely to be reachable for most users. Because the flaw exists within internal Kubernetes orchestration components, it is not typically exposed to the public internet. If your Fission interfaces are kept within an internal network and managed exclusively by authorized DevOps teams, the practical risk is significantly lower than for configurations that might be exposed externally.

What should I do if I use Fission?

The most effective response is to update your Fission installation to version 1.24.0 or later, which includes the necessary validation logic to block dangerous fields. Start by locating all active Fission instances within your infrastructure and identifying the teams responsible for managing them. Coordinate with those owners to schedule a maintenance window for the update, ensuring that you test the change in a staging environment first.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.