CVE-2026-71250CWE-918ssrf

CVE-2026-71250

Medium · published August 5, 2026

CVSS v3.1

4.3

EPSS

Percentile

19.0

In the wild

Unconfirmed

What it is

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.

The record

Technical detail

CVSS v3.1: 4.3 · MEDIUM
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
CVSS v4.0: Not supplied
EPSS: 0.00276 · 19.0th percentile
Weakness: CWE-918 · Server-Side Request Forgery (SSRF)
Published: 2026-08-05T15:16Z

References (1)

https://github.com/firefly-iii/firefly-iii · 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c

EPSS history

Timeline

05 AUG 10:57Z
Firefly III - Webhook URL Validation Explicitly Allows Loopback and Is Bypassable via DNS Rebinding
cvelistv5