vulnerability / NVI-00013115 / Revision 2
ip-address: Address6.isLinkLocal() recognizes fe80::/64 rather than fe80::/10, allowing SSRF and trust-boundary bypass to on-link hosts
GitHub lists this reviewed advisory for ip-address. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
6.3 MEDIUM (4.0)
security-advisories@github.com severity; no combined Null risk score.
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
ip-address
source listed<= 10.5.0
### Summary `Address6.isLinkLocal()` recognizes `fe80::/64` rather than `fe80::/10`. Link-local unicast is the whole `/10` under RFC 4291 §2.4 and the IANA IPv6 Special-Purpose Address Registry, so the method returns `false` for every link-local address outside the one `/64` that stateless address autoconfiguration happens to use. `new Address6('fe81::1').isLinkLocal()` is `false`. The library contradicts itself on the same object: for `fe81::1`, `getType()` returns `'Link-local unicast'`, `getScope()` returns `'Link local'`, and `isHostInSubnet(new Address6('fe80::/10'))` returns `true`, while `isLinkLocal()` returns `false`. An application that builds a network trust-boundary decision on these checks (for example a filter intended to block Server-Side Request Forgery, or SSRF) will classify a link-local target as unremarkable and allow the request. SSRF is an attack in which a user-supplied address coaxes the server into making a request to an internal destination the user could not otherwise reach. ### Details `isLinkLocal()` in `src/ipv6.ts` compares the first 64 bits of the address against a literal string: ```ts // Zeroes are required, i.e. we can't check isHostInSubnet
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. NIST National Vulnerability Database
A fixed release is not deployment evidence.
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04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
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05 / Provenance
Sources you can inspect
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- GHSA-rpw4-54j3-4h4q ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
- CVE-2026-101913 ↗
NIST National Vulnerability Database · official catalog
Observed . This product uses data from the NVD API but is not endorsed or certified by the NVD.
Public revision history
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- Revision 2 ·
Source facts changed; compare the preserved prior revision.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.