CVE-2026-44635 Kysely: JSON-path traversal injection via unsanitized path-leg metacharacters in `JSONPathBuilder.key()` / `.at()`
Attackers can traverse JSON sub-fields outside intended scope via unsanitized path metacharacters in Kysely query builder, leading to unauthorized data access or modification.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-44635?
CVE-2026-44635 is a high-severity path traversal vulnerability in kysely-org kysely, published on 27 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-44635?
2 open source packages ship an affected version, including kysely.
| Package | Affected | Fixed in |
|---|---|---|
kysely npm | From 0.26.0 | 0.28.17 |
kysely npm | From 0.26.0 | 0.28.17 |
How do I fix CVE-2026-44635?
Upgrade kysely to 0.28.17 or later.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-44635 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-44635 exists.
Sources
Also known as GHSA-pv5w-4p9q-p3v2, MINI-86x4-jc2c-g6h2, MINI-q9x3-hh68-rr8f.