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Not in CISA KEV
HIGH severity

CVE-2021-23490 — parse-link-header

HIGHFix: thlorenz/parse-link-header@72f05c7

CVE-2021-23490 is a high-severity (CVSS 7.5) CWE-1333 vulnerability in parse-link-header. 2 public exploit references exist, so weaponization risk is real. A fix is available for parse-link-header — see the affected versions and patch details below.

Uncontrolled Resource Consumption in parse-link-header

Also known asGHSA-q674-xm3x-2926
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
2 known
Exploitation data as of Oct 10, 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 CVEs78th percentile — riskier than 78% of all scored CVEsHighest risk
0.00%0.78%1.55%2.33%0.4%1.8%Apr 26Aug 26Oct 26

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

How urgent is this, really

CVE-2021-23490 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,738 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.

341other npm packages depend on this — each one inherits the vulnerability until it's patched upstream
parse-link-headernpm
2.5Mdownloads / week

Description

The package parse-link-header before 2.0.0 are vulnerable to Regular Expression Denial of Service (ReDoS) via the checkHeader function.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
📦npmparse-link-headerall versions2.0.0npm install parse-link-header@2.0.0

Affected Products

1 product · 1 configurations
Application
parse-link-headerparse-link-header_project
< 2.0.0
range
Exploits & PoCs
2

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

The package parse-link-header before 2.0.0 are vulnerable to Regular Exp…

snyk.ioNVDJan 2022

The package parse-link-header before 2.0.0 are vulnerable to Regular Exp…

snyk.ioNVDJan 2022

Detection & mitigation playbook

Open-source dependency

  1. Detect

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

  2. Fix

    Update parse-link-header to 2.0.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-23490 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 package parse-link-header before 2.0.0 are vulnerable to Regular Expression Denial of Service (ReDoS) via the checkHeader function.
O3 Security · Impact-Aware SCA

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CVE-2021-23490: parse-link-header DoS — Fixed in 2.0.0