Tilt: Cross-site WebSocket hijacking of the Tilt HUD stream

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

8.3 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-55883: 0.26% estimated exploitation activity in the next 30 days; percentile 18.11 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary The Tilt HUD WebSocket (/ws/view) is gated by a CSRF token, but the token is served by an unauthenticated endpoint and the upgrader accepts any client that omits an Origin header. When the HUD is network-exposed, an attacker can open the HUD stream and read the developer's session state. Details The upgrader accepts a connection when the csrf query parameter matches a process-wide token (websocketCSRFToken). That token is served as text/plain by an unauthenticated handler (WebsocketToken, mounted at /api/websockettoken), so any reachable caller can fetch it and connect to /ws/view?csrf=<token. When the parameter does not match, the upgrader falls back to a same-origin check that returns true when the Origin header is absent, so a non-browser client that omits Origin is accepted anyway. The token has no per-session binding. Impact An attacker who can reach the HUD listener can open the HUD WebSocket and receive the full view stream — session state, Tiltfile contents, resource…

Published by the source

19 Jun 2026, 13:53 UTC

Last modified by the source

21 Jul 2026, 13:44 UTC

Source last checked

26 Oct 2026, 15:27 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-6m68-r693-78qx

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# Patch Next advisory brief: CVE-2026-55883

Advisory: Tilt: Cross-site WebSocket hijacking of the Tilt HUD stream
IDs: CVE-2026-55883, GHSA-6m68-r693-78qx
Record: https://patchnext.com/advisories/cve-2026-55883 (revision 1, source checked 26 Oct 2026, 15:27 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/tilt-dev/tilt 0.37.4. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/tilt-dev/tilt: affected >= 0.24.0, <= 0.37.3; fixed in 0.37.4

## Suggested inspection (read-only)
- Go github.com/tilt-dev/tilt: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/tilt-dev/tilt.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-6m68-r693-78qx (GitHub-reviewed advisory GHSA-6m68-r693-78qx lists affected ranges: Go github.com/tilt-dev/tilt >=0.24.0 <=0.37.3)

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