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MEDIUM severity

CVE-2021-23718 — ssrf-agent

MEDIUMFix: welefen/ssrf-agent@9607175

CVE-2021-23718 is a medium-severity (CVSS 6.5) Server-Side Request Forgery (SSRF) vulnerability in ssrf-agent. 1 public exploit reference exists, so weaponization risk is real. A fix is available for ssrf-agent — see the affected versions and patch details below.

Server-Side Request Forgery in ssrf-agent

Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
1 known
Exploitation data as of Oct 12, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.6%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs75th percentile — riskier than 75% of all scored CVEsHighest risk
0.00%0.71%1.41%2.12%0.4%1.6%Apr 26Aug 26Oct 26

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

How urgent is this, really

CVE-2021-23718 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,987 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.

0other npm packages depend on this — each one inherits the vulnerability until it's patched upstream
ssrf-agentnpm
94downloads / week

Description

The package ssrf-agent before 1.0.5 are vulnerable to Server-side Request Forgery (SSRF) via the defaultIpChecker function. It fails to properly validate if the IP requested is private.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
📦npmssrf-agentall versions1.0.5npm install ssrf-agent@1.0.5

Affected Products

1 product · 1 configurations
Application
ssrf-agentssrf-agent_project
< 1.0.5
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.

The package ssrf-agent before 1.0.5 are vulnerable to Server-side Reques…

snyk.ioNVDNov 2021

Detection & mitigation playbook

Open-source dependency

  1. Detect

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

  2. Fix

    Update ssrf-agent to 1.0.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-23718 is resolved across your whole dependency graph.

  3. Workarounds

    Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.

Frequently Asked Questions

The package ssrf-agent before 1.0.5 are vulnerable to Server-side Request Forgery (SSRF) via the defaultIpChecker function. It fails to properly validate if the IP requested is private.
O3 Security · Impact-Aware SCA

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CVE-2021-23718: ssrf-agent SSRF — Fixed in 1.0.5