SiYuan: A parser differential between the WebSocket keepalive exemption and the session quarantine allows unauthenticated access to the broadcast event stream

Exploitation

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

CVSS

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

EPSS

• CVE-2026-73054: 0.41% estimated exploitation activity in the next 30 days; percentile 35.11 (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 Two checks on the same WebSocket request URI parse it differently. The authentication exemption for keepalive sessions matches raw substrings, while the quarantine introduced to contain those sessions reads a parsed query parameter. Because Go's url.Values.Get returns only the first value for a repeated key, a single URI can satisfy the exemption and still resolve to a non-auth session identity. The result is that an unauthenticated remote caller connects to the kernel WebSocket with a valid access auth code configured, is placed in the general broadcast pool rather than the quarantined pool, and receives the live event stream. Details The exemption matches substrings. kernel/server/serve.go:1222 on the development branch, :1074 on master: Neither operand is parsed. Any URI containing both literals is exempted, regardless of what the query actually resolves to. The quarantine parses. Commit 1e370e373 added the containment for exempted sessions at kernel/util/websocket.go:171:…

Published by the source

23 Oct 2026, 18:34 UTC

Last modified by the source

23 Oct 2026, 18:45 UTC

Source last checked

26 Oct 2026, 15:32 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-c8w8-3pqp-wr83

2. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-c8w8-3pqp-wr83

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-c8w8-3pqp-wr83

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-73054

Advisory: SiYuan: A parser differential between the WebSocket keepalive exemption and the session quarantine allows unauthenticated access to the broadcast event stream
IDs: CVE-2026-73054, GHSA-c8w8-3pqp-wr83
Record: https://patchnext.com/advisories/cve-2026-73054 (revision 3, source checked 26 Oct 2026, 15:32 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/siyuan-note/siyuan/kernel 0.0.0-20260731131820-67bc300b6ea6. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/siyuan-note/siyuan/kernel: affected < 0.0.0-20260731131820-67bc300b6ea6; fixed in 0.0.0-20260731131820-67bc300b6ea6

## Suggested inspection (read-only)
- Go github.com/siyuan-note/siyuan/kernel: 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/siyuan-note/siyuan/kernel.
- 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://osv.dev/vulnerability/GHSA-c8w8-3pqp-wr83 (OSV record GHSA-c8w8-3pqp-wr83 lists affected ranges: Go github.com/siyuan-note/siyuan/kernel >=0 <0.0.0-20260731131820-67bc300b6ea6 (fixed))
- Verified: https://github.com/advisories/GHSA-c8w8-3pqp-wr83 (GitHub-reviewed advisory GHSA-c8w8-3pqp-wr83 lists affected ranges: Go github.com/siyuan-note/siyuan/kernel >=0 <0.0.0-20260731131820-67bc300b6ea6)

Commands are suggestions: review each one before running it.