🛡️ fix: Cover full fe80::/10 link-local range in IPv6 check#12244
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The `isPrivateIP` check used `startsWith('fe80')` which only matched
fe80:: but missed fe90::–febf:: (the rest of the RFC 4291 fe80::/10
link-local block). Replace with a proper bitwise hextet check.
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Pull request overview
This PR tightens SSRF protection by correctly detecting the full IPv6 link-local range fe80::/10 (RFC 4291) instead of only matching fe80:: via string prefix.
Changes:
- Added a dedicated helper to detect
fe80::/10via a bitmask on the first hextet. - Updated
isPrivateIP()to use the new helper for IPv6 link-local detection. - Expanded Jest coverage to include
fe90–febfand thefec0boundary case for bothisSSRFTarget()andisPrivateIP().
Reviewed changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.
| File | Description |
|---|---|
| packages/api/src/auth/domain.ts | Replaces startsWith('fe80') with a bitmask-based fe80::/10 link-local check. |
| packages/api/src/auth/domain.spec.ts | Adds tests to ensure the full fe80::/10 range is blocked and validates boundary behavior. |
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…ames
parseInt('fe90.example.com', 16) stops at the dot and returns 0xfe90,
which passes the bitmask check and false-positives legitimate domains.
Add colon-presence guard (IPv6 literals always contain ':') and a hex
regex validation on the first hextet before parseInt.
Also document why fc/fd use startsWith while fe80::/10 needs bitwise.
- Assert fe90/fea0/febf hostnames are NOT blocked (regression guard) - Add feb0::1 and bracket form [fe90::1] to isPrivateIP coverage - Extend resolveHostnameSSRF tests for fe90::1 and febf::1
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…ila#12244) * 🛡️ fix: Cover full fe80::/10 link-local range in SSRF IPv6 check The `isPrivateIP` check used `startsWith('fe80')` which only matched fe80:: but missed fe90::–febf:: (the rest of the RFC 4291 fe80::/10 link-local block). Replace with a proper bitwise hextet check. * 🛡️ fix: Guard isIPv6LinkLocal against parseInt partial-parse on hostnames parseInt('fe90.example.com', 16) stops at the dot and returns 0xfe90, which passes the bitmask check and false-positives legitimate domains. Add colon-presence guard (IPv6 literals always contain ':') and a hex regex validation on the first hextet before parseInt. Also document why fc/fd use startsWith while fe80::/10 needs bitwise. * ✅ test: Harden IPv6 link-local SSRF tests with false-positive guards - Assert fe90/fea0/febf hostnames are NOT blocked (regression guard) - Add feb0::1 and bracket form [fe90::1] to isPrivateIP coverage - Extend resolveHostnameSSRF tests for fe90::1 and febf::1
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The
isPrivateIPcheck usedstartsWith('fe80')which only matched fe80:: but missed fe90::–febf:: (the rest of the RFC 4291 fe80::/10 link-local block). Replace with a proper bitwise hextet check.