CVE-2026-55473

MEDIUMCVSS 6/10EPSS 0.24%

Last modified

CVE-2026-55473 is a medium-severity vulnerability rated 6/10 on the CVSS scale. 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. EPSS estimates a 0.24% chance of exploitation in the next 30 days.

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.

Metrics

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
sysadminsmediahomebox< 0.26.0

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is CVE-2026-55473?
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.
How severe is CVE-2026-55473?
CVE-2026-55473 has a CVSS score of 6/10 (MEDIUM severity). The EPSS model estimates a 0.24% probability of exploitation in the next 30 days.
How do I fix CVE-2026-55473?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST