CVE-2026-54452: safeurl is Missing IPv6 CIDR Ranges in Blocklist

July 15, 2026

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)

References

github.com/advisories/GHSA-xgch-x3mx-cm3c
github.com/doyensec/safeurl/releases/tag/v0.2.4
github.com/doyensec/safeurl/security/advisories/GHSA-xgch-x3mx-cm3c
nvd.nist.gov/vuln/detail/CVE-2026-54452

Code Behaviors & Features

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