# 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.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 27 May 2026
- **Updated:** 28 May 2026
- **Also known as:** GHSA-pv5w-4p9q-p3v2, MINI-86x4-jc2c-g6h2, MINI-q9x3-hh68-rr8f

## 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.

Weakness: CWE-915 (Improperly Controlled Modification of Dynamically-Determined Object Attributes), CWE-89 (Improper Neutralization of Special Elements used in an SQL Command), CWE-22 (Improper Limitation of a Pathname to a Restricted Directory), CWE-1284 (Improper Validation of Specified Quantity in Input)

## Which versions are affected by CVE-2026-44635?

2 open source packages ship an affected version, including kysely.


| Package | Ecosystem | 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.

## Is CVE-2026-44635 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-44635 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-44635 and fix it if it is affected.

What it is: 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.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-44635 exists.

Affected packages and fixed versions:
- kysely (npm): affected from 0.26.0; fixed in 0.28.17
- kysely (npm): affected from 0.26.0; fixed in 0.28.17

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-44635/ (Markdown: https://insights.sbomify.com/CVE-2026-44635/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-44635
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-44635
- OSV: https://osv.dev/vulnerability/CVE-2026-44635

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-44635/
Summaries are generated and may contain mistakes; the official description above is the record.