CVE-2026-50554 is a medium-severity (CVSS 5.3) Information Exposure vulnerability in github.com/enchant97/note-mark/backend. A fix is available for github.com/enchant97/note-mark/backend — see the affected versions and patch details below.
Note Mark: Unauthenticated disclosure of soft-deleted note metadata via deleted=true on public books in note-mark
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-50554.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-50554 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
github.com/enchant97/note-mark/backendReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Note Mark is an open-source note-taking application. Prior to version 0.19.5, GET /api/books/{bookID}/notes is an unauthenticated endpoint that accepts a "deleted" query parameter. When the request is ?deleted=true, the service runs the query with Unscoped() (bypassing GORM's soft-delete scope) but keeps the read-authorization clause as "owner_id = ? OR is_public = ?". As a result, any unauthenticated caller can enumerate the metadata of soft-deleted ("trashed") notes belonging to any public book — notes the owner explicitly deleted and expected to be removed from public view. This issue has been patched in version 0.19.5.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/enchant97/note-mark/backend | all versions | 0.0.0-20260601210758-9c9b72740f22go get github.com/enchant97/note-mark/backend@v0.0.0-20260601210758-9c9b72740f22 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/enchant97/note-mark/backend, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/enchant97/note-mark/backend to 0.0.0-20260601210758-9c9b72740f22 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-50554 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-50554 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-50554. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-50554 in your dependencies?
O3 Security finds CVE-2026-50554 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.