Node.js Permission Model bypass in fs.realpathSync.native()
CVE-2026-21715 is a low-severity information disclosure vulnerability in the Node.js Permission Model. In affected Node.js 20.x, 22.x, 24.x, and 25.x releases, the filesystem API fs.realpathSync.native() does not enforce the expected read permission checks when a process is started with --permission and restricted --allow-fs-read settings. While comparable filesystem functions correctly honor the configured read restrictions, fs.realpathSync.native() can still be invoked to resolve paths outside the permitted read scope. This allows untrusted or constrained code to test whether files exist, resolve symlink targets, and enumerate filesystem paths beyond directories explicitly allowed by the Permission Model.
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Impact, mitigation & remediation
What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.
Impact
What an attacker gets, and what they’ve been doing with it.
Mitigation
If you can’t patch tonight, do this now.
Remediation
Patch, then assume compromise.
Exploits
No public exploits tracked yet. Mallory keeps watching.
No public exploit code observed for this vulnerability.
Affected products & vendors
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
8 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A low-severity Node.js Permission Model issue where fs.realpathSync.native() bypasses read permission checks and can disclose file existence.
A low-severity Node.js permission model bypass that allows filesystem path disclosure outside permitted directories via fs.realpathSync.native().
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.