Vulnerability · Published Aug 5, 2026 · Assigned by TuranSec
CVE-2026-71250Firefly III - Webhook URL Validation Explicitly Allows Loopback and Is Bypassable via DNS Rebinding
Medium 4.3
In plain English
A medium-severity server-side request forgery in firefly-iii from firefly-iii. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 20% of all known vulnerabilities).
Severity (CVSS 3.1)4.3Medium
Exploit odds (30 days)0.3%top 79.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| firefly-iii | firefly-iii | 0 |
Weakness: CWE-918 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
References
- https://github.com/firefly-iii/firefly-iii third-party-advisory