SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityDeferred

CVE-2026-71250

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…

MEDIUM 4.3EPSS 0.22%

Does this matter?

Lower severity and a low EPSS score (0.22%). Track it; it rarely justifies an emergency change on its own.

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.

CVSS 3.1
4.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
EPSS
0.22% probability · 12th percentile
CISA KEV
Not listed
Weakness
CWE-918
Source
309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.