HomeBox: Cross-Tenant IDOR in Notifier Update Leaks Shoutrrr Credentials and Allows Webhook Hijack

published 2026-09-21 48 d ago modified 2026-09-23 46 d ago also EUVD-2026-84033

cvss: 8.1; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 39%
public exploits: 0; none known

HomeBox is a home inventory and organization system. Prior to 0.26.0, NotifierRepository.Update in backend/internal/data/repo/repo_notifier.go updates a notifier through UpdateOneID(id) without requiring the record's user ID to match the authenticated user. An authenticated user who supplies another tenant's notifier UUID to PUT /v1/notifiers/{id} can read the returned stored url, which may contain plaintext Shoutrrr credentials for Slack, SMTP, Telegram, Pushover, or Discord, and can replace the URL to redirect the victim's notifications to an attacker-controlled webhook. This issue is fixed in version 0.26.0.

Patch / fix

links 2

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 48 d ago (2026-09-21)

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	8.1	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Affected products

sysadminsmedia homebox

Classification

Weakness

CWE-522 Insufficiently Protected Credentials
CWE-639 Authorization Bypass Through User-Controlled Key

References

Sources

CVE List CVE-2026-48976
NVD CVE-2026-48976

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary