CVE-2026-21715: Low severity Node.js Node.js vulnerability
A flaw in Node.js Permission Model filesystem enforcement leaves fs.realpathSync.native() without the required read permission checks, while all comparable filesystem functions correctly enforce them.
As a result, code running under --permission with restricted --allow-fs-read can still use fs.realpathSync.native() to check file existence, resolve symlink targets, and enumerate filesystem paths outside of permitted directories.
This vulnerability affects 20.x, 22.x, 24.x, and 25.x processes using the Permission Model where --allow-fs-read is intentionally restricted.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Compensating control
For Node.js processes using the Permission Model, avoid relying on `--allow-fs-read` restrictions as a control against filesystem access via `fs.realpathSync.native()` until the affected Node.js versions are remediated.
Event History
Frequently Asked Questions
What is the severity of CVE-2026-21715?
CVE-2026-21715 has a high severity due to the lack of required read permission checks in the `fs.realpathSync.native()` function.
How do I fix CVE-2026-21715?
To fix CVE-2026-21715, update to the latest version of Node.js that addresses this vulnerability.
What software versions are affected by CVE-2026-21715?
CVE-2026-21715 affects Node.js versions from 20.0.0 to 21.0.0, 22.0.0 to 23.0.0, 24.0.0 to 25.0.0, and 25.0.0 to 26.0.0.
Can CVE-2026-21715 be exploited?
Yes, CVE-2026-21715 can be exploited by running code with the `--permission` flag, allowing unauthorized filesystem read operations.
What environments are most at risk from CVE-2026-21715?
Environments running Node.js applications with restricted filesystem permissions using `--allow-fs-read` are at the highest risk from CVE-2026-21715.