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📦
📦 npm
Not in CISA KEV
HIGH severity

CVE-2020-7661

HIGH

CVE-2020-7661 is a high-severity (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in url-regex. 5 public exploit references exist, so weaponization risk is real. O3 Security confirms whether CVE-2020-7661 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

Regular expression denial of service in url-regex

Published
Jun 22, 2020
Updated
Mar 13, 2026
Affected
1 pkg
Patched
None yet
Exploits
5 known
Exploitation data as of Mar 13, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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.

200other npm packages depend on this — each one inherits the vulnerability until it's patched upstream
url-regexnpm
343Kdownloads / week

Description

all versions of url-regex are vulnerable to Regular Expression Denial of Service. An attacker providing a very long string in String.test can cause a Denial of Service.

Affected Packages

1 total
EcosystemPackageVulnerable rangeFix
📦npmurl-regexall versionsNo fix
Exploits & PoCs
5

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 url-regex. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Remediation status

    No patched version of url-regex has shipped for CVE-2020-7661 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.

  3. Mitigate without a patch

    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.

  4. How O3 protects you

    O3 pinpoints whether CVE-2020-7661 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2020-7661. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

all versions of url-regex are vulnerable to Regular Expression Denial of Service. An attacker providing a very long string in String.test can cause a Denial of Service.
O3 Security · Impact-Aware SCA

Is CVE-2020-7661 in your dependencies?

O3 detects CVE-2020-7661 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

CVE-2020-7661: Regular expression denial of… | O3 Security