---
id: "CVE-2026-102339"
kind: "vulnerability"
aliases: ["CVE-2026-102339"]
title: "Telepresence: attacker can hijack another user's cluster tunnel session"
severity: "high"
cvss: 8.2
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["infrastructure", "kubernetes", "openshift", "telepresence", "traffic-manager"]
not_affected_if: ["telepresence-not-used", "version-2.31.0-or-later"]
published_at: "2026-11-04T21:17:40+00:00"
first_seen_at: "2026-11-04T21:49:16+00:00"
updated_at: "2026-11-04T21:50:45+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-102339", "first_seen_at": "2026-11-04T21:49:16+00:00"}]
exploit_sources: []
---

# Telepresence: attacker can hijack another user's cluster tunnel session

Telepresence, a tool for running local development against a remote Kubernetes or OpenShift cluster, fails to check that a caller owns a tunnel session before attaching to it. An attacker who obtains a valid active session ID can attach a routed tunnel and use that session's network routing into the cluster.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed Telepresence version with `telepresence version` and compare it against the fixed release.
- Look for the Traffic Manager deployed in the cluster and check its image version.
- Review whether the `ArriveAsClient` endpoint is reachable from outside the cluster network.

## Fix

- Telepresence: move to `2.31.0` or later.

## Timeline

- 2026-11-04T21:49:16+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-102339

## Documents

- [advisory] Vendor advisory: github.com https://github.com/telepresenceio/telepresence/security/advisories/GHSA-6j3h-rp73-6rvf
- [fix] Patch: github.com https://github.com/telepresenceio/telepresence/commit/1312482488b771742dbedd3015f9a81a27532de6
- [fix] Patch: github.com https://github.com/telepresenceio/telepresence/commit/36458b65a010d2b316af48cd90e193ba190785d9
- [fix] Release notes: github.com https://github.com/telepresenceio/telepresence/releases/tag/v2.31.0

## From the sources

Telepresence enables local development against a remote Kubernetes or OpenShift cluster. Prior to 2.31.0, the Traffic Manager Tunnel gRPC streaming endpoint parses a session ID from the first bytes of a caller-controlled message in pkg/tunnel/message.go and passes it to state.Tunnel without verifying that the caller owns the active session. An attacker who obtains a valid active session ID through log leakage, cluster-internal channels, or the unauthenticated ArriveAsClient endpoint can attach a routed tunnel to that session and gain its network routing capabilities. UUID4 session IDs make cold brute force impractical. This vulnerability is fixed in 2.31.0.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_