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Missing IPv6 CIDR Ranges in Blocklist

Moderate
v1ktor0t published GHSA-xgch-x3mx-cm3c Jun 4, 2026

Package

No package listed

Affected versions

<0.2.4

Patched versions

0.2.4

Description

The privateNetworks blocklist was found to be missing newly added CIDR ranges. More specifically, the following CIDR ranges were not being blocked:

  • 64:ff9b:1::/48: NAT64 local-use prefix (RFC 8215)
  • 5f00::/16: Segment Routing (SRv6) SIDs (RFC 9602)
  • 3fff::/20: documentation prefix (RFC 9637)
  • 100:0:0:1::/64: Dummy IPv6 Prefix (RFC 9780)

Impact

If exploited, an attacker would potentially be able to reach resources hosted on the IPs residing in the missing ranges.

Workarounds

Disable IPv6 by setting EnableIPv6(false). This is the default behavior of the library.

Resolution

Upgrade to v0.2.4

Credits

Thanks to @tonghuaroot for reporting.

Severity

Moderate

CVE ID

CVE-2026-54452

Weaknesses

Server-Side Request Forgery (SSRF)

The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. Learn more on MITRE.

Credits