GHSA-p4hc-9pjh-55c8 is a high-severity (CVSS 7.5) Server-Side Request Forgery (SSRF) vulnerability in ssrfcheck. A fix is available for ssrfcheck — see the affected versions and patch details below.
ssrfcheck: SSRF Bypass Caused by Failure to Classify Reserved IP Address Space as Invalid
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for GHSA-p4hc-9pjh-55c8.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-p4hc-9pjh-55c8 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,567 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
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.
ssrfchecknpmDescription
SSRF Bypass in ssrfcheck - fails to classify reserved IP address space as invalid
ssrfcheck is an npm package that serves to provide protection from SSRF by validating URLs or hostname inputs.
Resources:
- Project's GitHub code repository: https://github.com/felippe-regazio/ssrfcheck
- Project's npm package: https://www.npmjs.com/package/ssrfcheck
Vulnerability
The ssrfcheck package maintains a denylist of IP addresses and ranges to check against when validating if an IP address is to be considered as safe or not.
However, the IP address list used for the denylist is incomplete and misses a reserved IP address space as defined by the IANA (Internet Assigned Numbers Authority):
- 224.0.0.0/4 - Multicast
Practically, this reserved IP address space is used for multicast traffic and would most commonly be used for reserved local communication over network protocols such as UDP, which would make it less likely to be used in a typical SSRF attack in practice.
However, such reserved IP address space shouldn't be allowed and it would be responsible of the SSRF protection package to align and conform to an agreed-upon standard of special-purposed addresses that should not be considered a valid public IP address. For reference, the popular npm packages private-ip and ipaddr.js that are highly dependent-upon to make decisions about SSRF protection and both consider the above mentioned IP address space as reserved and is not considered a valid public IP address.
Exploit Proof of Concept
- Install the
ssrfcheckpackage:
npm install ssrfcheck
- Define an
app.jsfile with the programmatic API ofssrfcheck:
import { isSSRFSafeURL } from 'ssrfcheck';
let result
result = isSSRFSafeURL('https://012.1.2.3/whatever');
console.log(result); // returns false
result = isSSRFSafeURL('https://localhost:8080/whatever');
console.log(result); // returns false
result = isSSRFSafeURL('https://239.255.255.250:8080/whatever');
console.log(result); // returns true - bypassed
Vulnerable versions
All versions of ssrfcheck are vulnerable to this issue, up to and including to the latest version of 1.1.1.
Assigned CVE
Author
Liran Tal
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | ssrfcheck | all versions | 1.2.0npm install ssrfcheck@1.2.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ssrfcheck, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update ssrfcheck to 1.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-p4hc-9pjh-55c8 is resolved across your whole dependency graph.
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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-p4hc-9pjh-55c8 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-p4hc-9pjh-55c8. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-p4hc-9pjh-55c8 in your dependencies?
O3 Security finds GHSA-p4hc-9pjh-55c8 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.