GHSA-xpcf-pg52-r92g is a medium-severity (CVSS 5.3) CWE-180 vulnerability in hono. O3 Security confirms whether GHSA-xpcf-pg52-r92g is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Hono has incorrect IP matching in ipRestriction() for IPv4-mapped IPv6 addresses
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.
hononpmDescription
Summary
ipRestriction() does not canonicalize IPv4-mapped IPv6 client addresses (e.g. ::ffff:127.0.0.1) before applying IPv4 allow or deny rules. In environments such as Node.js dual-stack, this can cause IPv4 rules to fail to match, leading to unintended authorization behavior.
Details
The middleware classifies client addresses based on their textual form. Addresses containing ":" are treated as IPv6, including IPv4-mapped IPv6 addresses such as ::ffff:127.0.0.1. These addresses are not normalized to IPv4 before matching.
As a result:
- IPv4 static rules (e.g.
127.0.0.1) do not match because the raw string differs - IPv4 CIDR rules (e.g.
127.0.0.0/8,10.0.0.0/8) are skipped because the address is treated as IPv6
For example, with:
denyList: ['127.0.0.1']
a request from 127.0.0.1 may be represented as ::ffff:127.0.0.1 and bypass the deny rule.
This behavior commonly occurs in Node.js environments where IPv4 clients are exposed as IPv4-mapped IPv6 addresses.
Impact
Applications that rely on IPv4-based ipRestriction() rules may incorrectly allow or deny requests.
In affected deployments, a denied IPv4 client may bypass access restrictions. Conversely, legitimate clients may be rejected when using IPv4 allow lists.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | hono | all versions | 4.12.12 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for hono. 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.
Fix
Update hono to 4.12.12 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-xpcf-pg52-r92g 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 pinpoints whether GHSA-xpcf-pg52-r92g 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 GHSA-xpcf-pg52-r92g. 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-xpcf-pg52-r92g in your dependencies?
O3 detects GHSA-xpcf-pg52-r92g across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.