CVE-2026-44635
HIGHCVE-2026-44635 is a high-severity (CVSS 7.5) Path Traversal vulnerability in kysely. O3 Security confirms whether CVE-2026-44635 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Kysely: JSON-path traversal injection via unsanitized path-leg metacharacters in `JSONPathBuilder.key()` / `.at()`
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.
kyselynpmDescription
Kysely is a type-safe TypeScript SQL query builder. From 0.26.0 to 0.28.16, DefaultQueryCompiler.visitJSONPathLeg does not escape JSON-path metacharacters (., [, ], *, **, ?). When attacker-controlled input flows into eb.ref(col, '->$').key(input) or .at(input) — including type-safe code where the JSON column is shaped like Record<string, T> so K extends string is the inferred type — every dot becomes a path-leg separator, letting an attacker traverse from the intended key into sibling and child fields the developer never meant to expose. The result is read access (and, in update statements, write access) to JSON sub-fields outside the intended scope across MySQL, PostgreSQL ->$/->>$, and SQLite. This vulnerability is fixed in 0.28.17.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | kysely | ≥ 0.26.0&&< 0.28.17 | 0.28.17 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for kysely. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update kysely to 0.28.17 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-44635 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 pinpoints whether CVE-2026-44635 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-44635. 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-2026-44635 in your dependencies?
O3 detects CVE-2026-44635 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.