# CVE-2026-102339: Telepresence: Tunnel endpoint accepts caller-supplied session ID with no ownership proof — active client sessions hijackable

Status: published. Published: 2026-11-04. Updated: 2026-11-04.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- telepresenceio / telepresence: < 2.31.0 (affected). Source: CNA: GitHub_M

## Severity and prioritization

- CVSS 3.1: 8.2 (high); CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N; source: CNA: GitHub_M

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-639

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/telepresenceio/telepresence/security/advisories/GHSA-6j3h-rp73-6rvf (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/telepresenceio/telepresence/pull/4217 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/telepresenceio/telepresence/commit/1312482488b771742dbedd3015f9a81a27532de6 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/telepresenceio/telepresence/commit/36458b65a010d2b316af48cd90e193ba190785d9 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/telepresenceio/telepresence/releases/tag/v2.31.0 (CNA: GitHub_M; x_refsource_MISC)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-102339; retrieved 2026-11-04; source updated 2026-11-04

Revision: 51cbc4d2070978f39791d6ff3d0b6afa70a8c9a0e0343692d66f6f6f49088fff

Canonical: https://y2.dev/cve/CVE-2026-102339

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