obsidian-tc : Symlink read-ACL scope bypass via lexical path checks

Exploitation

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

CVSS

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

EPSS

• CVE-2026-77361: 0.11% estimated exploitation activity in the next 30 days; percentile 1.42 (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.

Impact ACL checks ran on the lexical vault-relative path while containment used the realpath. An in-vault symlink placed under an allowed glob, whose realpath resolved into a denied folder, passed the read ACL — an intra-vault read-ACL-scope bypass. It requires an out-of-band-planted symlink (no MCP tool creates one) and is not a vault-root escape. Patches Fixed in 1.3.1. Upgrade to = 1.3.1. ACL enforcement now derives the realpath vault-relative path and feeds a single unified predicate at every site. Workarounds Do not permit untrusted symlinks inside the vault.

Published by the source

23 Oct 2026, 17:28 UTC

Last modified by the source

23 Oct 2026, 17:45 UTC

Source last checked

26 Oct 2026, 13:07 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-c5xx-h28h-f682

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-c5xx-h28h-f682

3. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-c5xx-h28h-f682

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# Patch Next advisory brief: CVE-2026-77361

Advisory: obsidian-tc : Symlink read-ACL scope bypass via lexical path checks
IDs: CVE-2026-77361, GHSA-c5xx-h28h-f682
Record: https://patchnext.com/advisories/cve-2026-77361 (revision 3, source checked 26 Oct 2026, 13:07 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 4.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: obsidian-tc 1.3.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm obsidian-tc: affected < 1.3.1; fixed in 1.3.1

## Suggested inspection (read-only)
- `npm ls obsidian-tc --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## 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 obsidian-tc.
- 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-c5xx-h28h-f682 (GitHub-reviewed advisory GHSA-c5xx-h28h-f682 lists affected ranges: npm obsidian-tc >=0 <1.3.1)
- Verified: https://osv.dev/vulnerability/GHSA-c5xx-h28h-f682 (OSV record GHSA-c5xx-h28h-f682 lists affected ranges: npm obsidian-tc >=0 <1.3.1 (fixed))

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