What is the CVSS score of CVE-2026-50567?

CVE-2026-50567 has a CVSS 3.1 base score of 7.7 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N. EPSS exploitation probability: 0.0%.

Which versions of Fission are affected by CVE-2026-50567?

Fission Kubernetes serverless framework prior to version 1.25.0 contains a path traversal vulnerability in its archive processing that allows authenticated users to write files outside intended…. A patch is available.

How to fix or mitigate CVE-2026-50567?

24 hours: Identify all Fission deployments (versions < 1.25.0), document affected instances, and restrict network access to fission-fetcher components to trusted internal networks only; implement immediate role-based access controls to limit which authenticated users can submit package archives. 7 days: Deploy file integrity monitoring on Fission-managed volumes to detect unauthorized writes; audit recent archive uploads and review access logs for suspicious package submissions; enable verbose logging of Unarchive operations in pkg/utils/zip.go. 30 days: Plan and execute upgrade to Fission version 1.25.0 or later once released; evaluate alternative serverless frameworks if upgrade timeline is uncertain; conduct forensic analysis of logs to confirm no unauthorized writes occurred.

Fission CVE-2026-50567

EUVD-2026-36071 HIGH

Path Traversal (CWE-22)

2026-06-10 GitHub_M

GHSA-q6vm-xqc9-v3ff

Path Traversal Kubernetes

7.7

CVSS 3.1 · NVD

Severity by source

Vendor (GitHub_M) PRIMARY

HIGH

qualitative

NVD

7.7 HIGH

AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N

Primary rating from Vendor (GitHub_M).

CVSS VectorNVD

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Changed

Confidentiality

None

Integrity

High

Availability

None

Lifecycle Timeline

Patch available

Jun 10, 2026 - 20:01 EUVD

Source Code Evidence Fetched

Jun 10, 2026 - 18:47 vuln.today

Analysis Generated

Jun 10, 2026 - 18:47 vuln.today

CVE Published

Jun 10, 2026 - 17:30 nvd

HIGH 7.7

DescriptionNVD

Fission is an open-source, Kubernetes-native serverless framework that simplifies the deployment of functions and applications on Kubernetes. Prior to version 1.25.0, Unarchive in pkg/utils/zip.go joined each archive entry name with the destination directory via filepath.Join and wrote the result without checking whether the resolved path stayed under the destination. A zip entry named ../../tmp/evil therefore landed at /tmp/evil. An attacker who could control a Package.Spec.Source.URL or Deployment.URL archive could induce the fetcher (running as the per-environment pod's fission-fetcher sidecar) to write files anywhere that process could reach: into other tenants' /packages/<ns>/ directories, into mounted secret/config volumes, or into the fetcher's own binary. This issue has been patched in version 1.25.0.

Articles & Coverage 1

News 12 New Kubernetes Vulnerabilities - 5 Critical, 7 High Severity Jun 11, 2026

AnalysisAI

Path traversal in Fission Kubernetes serverless framework prior to version 1.25.0 allows authenticated tenants to write files outside the intended extraction directory by submitting a crafted package archive. The fetcher sidecar (fission-fetcher) processes attacker-controlled Package.Spec.Source.URL or Deployment.URL archives via Unarchive in pkg/utils/zip.go, where filepath.Join was used without verifying the resolved path stayed under the destination, enabling cross-tenant file overwrite, tampering with mounted secret/config volumes, or overwriting the fetcher binary itself. No public exploit identified at time of analysis and the issue is not listed in CISA KEV.

Technical ContextAI

Fission is an open-source, Kubernetes-native serverless/FaaS framework that pulls user-supplied function code as zip archives and unpacks them inside per-environment pods. The flaw is a classic zip-slip (CWE-22 path traversal) in pkg/utils/zip.go's Unarchive function: it called filepath.Join(dst, f.NameInArchive) and wrote the result directly, so an entry named '../../tmp/evil' resolved to /tmp/evil on the fetcher's filesystem. The patch in PR #3444 replaces this with Go's os.Root (os.OpenRoot) confinement, explicitly rejects absolute paths, entries beginning with '..', and symlink entries before any file operation. The fetcher sidecar runs as UID 10001 and shares the /packages volume with builder containers, so traversal can reach any path that UID can write - including other tenants' /packages/<namespace>/ directories and mounted secret/configmap volumes.

RemediationAI

Upgrade Fission to vendor-released patch version 1.25.0 or later, which replaces the unsafe filepath.Join extraction with an os.Root-confined extractor that also rejects absolute paths, parent-traversal entries, and symlink entries up front (PR https://github.com/fission/fission/pull/3444). Follow guidance in the GHSA advisory https://github.com/fission/fission/security/advisories/GHSA-q6vm-xqc9-v3ff. If immediate upgrade is not possible, restrict who can create or update Package and Function/Deployment objects via Kubernetes RBAC so only trusted operators can supply Source.URL/Deployment.URL archives (trade-off: blocks tenant self-service workflows), and require packages be sourced from a vetted internal registry rather than arbitrary attacker-controlled URLs. Additionally, harden the fetcher sidecar with a readOnlyRootFilesystem securityContext and drop any unnecessary volume mounts of secrets/configmaps so that even if traversal occurs, writable targets are minimized (trade-off: may break builder flows that depend on the shared /packages volume - validate in staging first).