Mailpit's IsInternalIP deny list function fails to block the Azure WireServer address 168.63.129.16 and the RFC 2765/6145 IPv4-translated IPv6 prefix, allowing server-side request forgery to internal destinations. Attackers can supply hostnames resolving to these addresses in message content to reach the link check API and proxy endpoint for accessing internal resources.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
Low
Partial data leak
Integrity
None
No data modification
Availability
None
No disruption
CVSS Vector v4.0
Weakness Type (CWE)
Vulnerable Products 1
| Configuration | From (including) | Up to (excluding) |
|---|---|---|
|
Axllent Mailpit
cpe:2.3:a:axllent:mailpit:*:*:*:*:*:*:*:*
|
— |
<= 1.31.0
|
References 4
https://github.com/axllent/mailpit
disclosure@vulncheck.com
https://github.com/axllent/mailpit/blob/v1.31.0/internal/tools/net.go
disclosure@vulncheck.com
https://github.com/axllent/mailpit/commit/a02821bf3424da9196e156c422370f4868a1d…
disclosure@vulncheck.com
https://www.vulncheck.com/advisories/mailpit-ssrf-deny-list-bypass-via-azure-me…
disclosure@vulncheck.com