safeurl is a server-side request forgery protection library. Prior to 0.2.4, the privateNetworks list in ip.go omits the IPv6 ranges 64:ff9b:1::/48, 5f00::/16, 3fff::/20, and 100:0:0:1::/64. When an application enables IPv6 with EnableIPv6(true), an attacker-controlled destination in one of these ranges is not recognized as non-public and can pass the SSRF destination check, potentially allowing access to resources hosted within the omitted ranges.
IPv6 is disabled by default, and configurations that retain EnableIPv6(false) are not exposed to this bypass. This issue is fixed in version 0.2.4.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
Present
Additional conditions required
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
Low
Partial data leak
Integrity
Low
Partial data modification
Availability
None
No disruption
CVSS Vector v4.0
Weakness Type (CWE)
References 4
https://github.com/doyensec/safeurl/commit/d8f1021ea535b276f92999f0ec865da40e46…
security-advisories@github.com
https://github.com/doyensec/safeurl/pull/12
security-advisories@github.com
https://github.com/doyensec/safeurl/releases/tag/v0.2.4
security-advisories@github.com
https://github.com/doyensec/safeurl/security/advisories/GHSA-xgch-x3mx-cm3c
security-advisories@github.com