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Not in CISA KEV
LOW severity

CVE-2017-18869 — chownr

LOWFix: isaacs/chownr@36a93e3

CVE-2017-18869 is a low-severity (CVSS 2.5) CWE-367 vulnerability in chownr. 1 public exploit reference exists, so weaponization risk is real. A fix is available for chownr — see the affected versions and patch details below.

Time-of-check Time-of-use (TOCTOU) Race Condition in chownr

Also known asGHSA-c6rq-rjc2-86v2
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
1 known
Exploitation data as of Oct 8, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
0.3%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs25th percentile — riskier than 25% of all scored CVEsHighest risk
0.00%0.28%0.56%0.84%0.1%0.0%0.3%0.3%Apr 26Oct 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2017-18869 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

611other npm packages depend on this — each one inherits the vulnerability until it's patched upstream
chownrnpm
109.4Mdownloads / week

Description

A TOCTOU issue in the chownr package before 1.1.0 for Node.js 10.10 could allow a local attacker to trick it into descending into unintended directories via symlink attacks.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
📦npmchownrall versions1.1.0npm install chownr@1.1.0

Affected Products

1 product · 1 configurations
Application
chownrchownr_project
< 1.1.0
range
Exploits & PoCs
1

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

A TOCTOU issue in the chownr package before 1.1.0 for Node.js 10.10 coul…

snyk.ioNVDJun 2020

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for chownr, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update chownr to 1.1.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2017-18869 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate
ProductFixed inAdvisory
Red Hat Software Collections for Red Hat Enterprise Linux 7rh-nodejs8-nodejs-0:8.17.0-2.el7RHSA-2020:2625

Frequently Asked Questions

A TOCTOU issue in the chownr package before 1.1.0 for Node.js 10.10 could allow a local attacker to trick it into descending into unintended directories via symlink attacks.
O3 Security · Impact-Aware SCA

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CVE-2017-18869: chownr — Fixed in 1.1.0