What’s Vulnerable › Vulnerabilities

CVE-2026-55473: HomeBox: Notifier SSRF guard misses NAT64 prefixes (64:ff9b::/96, 64:ff9b:1::/48) — generic:// URL reaches cloud metadata on NAT64 egress

• Severity: medium (CVSS 6.0 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-21 · updated 2026-09-29
• Weakness: CWE-918

Description

HomeBox is a home inventory and organization system. Prior to 0.26.0, the default-on BlockBogonNets and BlockCloudMetadata notifier SSRF protections in backend/internal/sys/validate/notifier_url.go do not inspect IPv4 destinations embedded in the NAT64 prefixes 64:ff9b::/96 and 64:ff9b:1::/48. An authenticated user can submit a generic:// notifier through POST /v1/notifiers or POST /v1/notifiers/test, and on a Homebox instance that egresses through NAT64/DNS64, the gateway can translate an accepted IPv6 destination to cloud metadata, localhost, or another internal IPv4 host. The notifier test path returns delivery result information, and Shoutrrr propagates the response, providing feedback that can disclose retrieved metadata such as temporary credentials. Without NAT64 egress, the crafted IPv6 destination is not routable, but the guard still incorrectly classifies it as safe. This issue is fixed in version 0.26.0.

Affected products

• sysadminsmedia homebox: before 0.26.0

References

• https://github.com/sysadminsmedia/homebox/commit/42c52f7f7566b7fbd8017352187af20f552a4471
• https://github.com/sysadminsmedia/homebox/releases/tag/v0.26.0
• https://github.com/sysadminsmedia/homebox/security/advisories/GHSA-r9pf-rg22-655m

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