SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityReceived

CVE-2026-76239

Stigmem before 0.9.0a11 fails to validate the delivery_address parameter when creating webhook subscriptions, allowing authenticated users to specify internal loopback and private network destinations.

MEDIUM 5.3EPSS 0.27%

Does this matter?

Lower severity and a low EPSS score (0.27%). Track it; it rarely justifies an emergency change on its own.

Description

Stigmem before 0.9.0a11 fails to validate the delivery_address parameter when creating webhook subscriptions, allowing authenticated users to specify internal loopback and private network destinations. Attackers can trigger matching fact-change events to cause the Stigmem server to issue server-side HTTP POST requests to internal services, enabling blind SSRF attacks against localhost and private network endpoints.

CVSS 4.0
5.3 MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS
0.27% probability · 18th percentile
CISA KEV
Not listed
Weakness
CWE-918
Source
disclosure@vulncheck.com

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