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HIGH severity

CVE-2016-2537 — is-my-json-valid

HIGHFix: mafintosh/is-my-json-valid@eca4beb

CVE-2016-2537 is a high-severity (CVSS 7.5) Improper Input Validation vulnerability in is-my-json-valid. A fix is available for is-my-json-valid — see the affected versions and patch details below.

Regular Expression Denial of Service in is-my-json-valid

Also known asGHSA-f522-ffg8-j8r6
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Oct 13, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.8%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs79th percentile — riskier than 79% of all scored CVEsHighest risk
0.00%0.78%1.57%2.35%0.5%1.8%Apr 26Aug 26Oct 26

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

How urgent is this, really

CVE-2016-2537 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 388,997 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.

343other npm packages depend on this — each one inherits the vulnerability until it's patched upstream
is-my-json-validnpm
1.4Mdownloads / week

Description

The is-my-json-valid package before 2.12.4 for Node.js has an incorrect exports['utc-millisec'] regular expression, which allows remote attackers to cause a denial of service (blocked event loop) via a crafted string.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
📦npmis-my-json-validall versions2.12.4npm install is-my-json-valid@2.12.4

Affected Products

1 product · 1 configurations
Application
is my json validis_my_json_valid_project
≤ 2.12.3
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

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

  2. Fix

    Update is-my-json-valid to 2.12.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2016-2537 is resolved across your whole dependency graph.

  3. Workarounds

    Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

The is-my-json-valid package before 2.12.4 for Node.js has an incorrect exports['utc-millisec'] regular expression, which allows remote attackers to cause a denial of service (blocked event loop) via a crafted string.
O3 Security · Impact-Aware SCA

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CVE-2016-2537: is-my-json-valid DoS — Fixed in 2.12.4