Node.js Permissions Model symlink path bypass
A high-severity flaw in the Node.js Permissions model allows bypass of filesystem restrictions enforced by --allow-fs-read and --allow-fs-write through crafted relative symlink paths. By chaining directories and symlinks, an attacker-controlled script that is only intended to access the current directory can traverse outside the permitted path and access files elsewhere on the filesystem. The issue breaks the isolation guarantees of the Node.js permission model for affected releases. The vulnerability affects users of the permission model on Node.js v20, v22, v24, and v25.
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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.
--allow-fs-read or --allow-fs-write to untrusted scripts on affected versions. Run untrusted code in stronger isolation boundaries such as containers, VMs, or dedicated sandboxes, and enforce least-privilege OS-level filesystem permissions to reduce impact if the Node.js permission model is bypassed.Remediation
Patch, then assume compromise.
Exploits
1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos.
Repository contains a Node.js proof-of-concept exploit for CVE-2025-55130 (Node.js Permission Model symlink escape). It demonstrates bypassing --allow-fs-read/--allow-fs-write restrictions by creating a deep directory chain within the allowed path, placing a symlink (link) that points to an absolute path (__dirname), and then appending enough ../ traversal segments after the symlink so that the permission check (performed on the pre-resolution string) passes while the resolved path escapes the sandbox. Structure/purpose: - README.md: Explains the vulnerability, affected versions (20.x<20.20.0, 22.x<22.22.0, 24.x<24.13.0, 25.x<25.3.0), and usage. - check.js: Local-only version range checker using process.version; not an exploit. - exploit.js: Main arbitrary file read PoC. Default target is /etc/passwd; accepts a target path as argv[2]. Builds ./pwn/... chain, symlinks to __dirname, computes traversal depth from __dirname, and reads via fs.readFileSync on the crafted path. - exploit_write.js: Arbitrary file write PoC. Default target is /tmp/pwned_<timestamp>.txt; accepts target path and content via argv. Uses fs.writeFileSync on the crafted escaped path. - exfil.js: Bulk exfiltration helper that iterates a hardcoded list of common sensitive Linux and $HOME files (SSH keys, AWS creds, Docker config, shell history, etc.) and attempts to read each via the same symlink+traversal technique; prints a small preview and stats. Capabilities: - Sandbox escape for filesystem operations under Node’s Permission Model. - Arbitrary file read (single target) and mass file read/exfiltration. - Arbitrary file write outside the allowed directory (can be used for persistence/priv-esc depending on environment). No network C2/endpoints are present; all actions are local filesystem operations. Cleanup routines remove created directories (./pwn, ./wpwn, ./exfil_chain) after execution.
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
22 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
Filesystem permissions bypass vulnerability in Node.js.
A high-severity Node.js vulnerability that could allow reading sensitive files via crafted relative symlink paths (as described in the content).
High-severity symlink-based permission bypass in Node.js permission model that can evade filesystem permission flags (e.g., --allow-fs-read) and enable arbitrary file access.
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.