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MEDIUM severity

CVE-2019-10795 — undefsafe

MEDIUMFix: remy/undefsafe@f272681

CVE-2019-10795 is a medium-severity (CVSS 6.3) CWE-74 vulnerability in undefsafe. 1 public exploit reference exists, so weaponization risk is real. A fix is available for undefsafe — see the affected versions and patch details below.

Prototype Pollution in undefsafe

Also known asGHSA-332q-7ff2-57h2SNYK-JS-UNDEFSAFE-548940
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
1 known
Exploitation data as of Oct 3, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.1%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs64th percentile — riskier than 64% of all scored CVEsHighest risk
0.00%0.53%1.06%1.59%0.3%1.1%Apr 26Aug 26Oct 26

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

How urgent is this, really

CVE-2019-10795 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.

127other npm packages depend on this — each one inherits the vulnerability until it's patched upstream
undefsafenpm
15.0Mdownloads / week

Description

undefsafe before 2.0.3 is vulnerable to Prototype Pollution. The 'a' function could be tricked into adding or modifying properties of Object.prototype using a proto payload.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
📦npmundefsafeall versions2.0.3npm install undefsafe@2.0.3

Affected Products

1 product · 1 configurations
Application
undefsafeundefsafe_project
< 2.0.3
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.

Detection & mitigation playbook

Open-source dependency
  1. Detect

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

  2. Fix

    Update undefsafe to 2.0.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2019-10795 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.

Frequently Asked Questions

undefsafe before 2.0.3 is vulnerable to Prototype Pollution. The 'a' function could be tricked into adding or modifying properties of Object.prototype using a __proto__ payload.
O3 Security · Impact-Aware SCA

Is CVE-2019-10795 in your dependencies?

Find it across npm, including transitive dependencies.

CVE-2019-10795: undefsafe — Fixed in 2.0.3