Firefly III - Webhook URL Validation Explicitly Allows Loopback and Is Bypassable via DNS Rebinding
13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 4.3epss 0.3%
exploitation probability
0.3%top 82% of all CVEs
observed exploitation
nono source reports it
Firefly III's webhook URL validator (IsValidWebhookUrl.php) filters most private/reserved IPv4 ranges but contains an explicit early-return that allows any resolved address in 127.0.0.0/8, permitting an authenticated user (with webhooks enabled, which is off by default) to configure a webhook targeting loopback services on the server.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Affected products
firefly-iii · firefly-iii