CVE-2026-55473

MEDIUMPre-NVD 6.06.0—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.0 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 67% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 3 sources updated this week
6.0EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.0Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
6.0
EG Score
6.0(medium)
EG Risk
32(Track)
EG Risk 32/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity60% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
33%
KEV
Not listed

Published

September 21, 2026

Last Modified

September 23, 2026

Advisory Details (3)

Auto-updated Sep 21, 2026
Patch available. Sources: github, github_commit, github_release.
github_release Patch Available

v0.26.0

Patch available: sysadminsmedia/homebox v0.26.0

https://github.com/sysadminsmedia/homebox/releases/tag/v0.26.0
github_commit

commit 42c52f7f7566 (sysadminsmedia/homebox)

Fix landed in sysadminsmedia/homebox commit 42c52f7f7566 — awaiting tagged release

https://github.com/sysadminsmedia/homebox/commit/42c52f7f7566b7fbd8017352187af20f552a4471
github Patch Available

Notifier SSRF guard misses NAT64 prefixes (64:ff9b::/96, 64:ff9b:1::/48) — generic:// URL reaches cloud metadata on NAT64 egress · Advisory · sysadminsmedia/homebox · GitHub

https://github.com/sysadminsmedia/homebox/security/advisories/GHSA-r9pf-rg22-655m

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 8× in last 7d / 8× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-24 20:21 UTCEG score recompute
  2. 2026-09-24 14:04 UTCEPSS rescore
  3. 2026-09-23 18:39 UTCEG score recompute
  4. 2026-09-23 17:54 UTCEPSS rescore
  5. 2026-09-22 20:09 UTCEG score recompute
  6. 2026-09-21 18:27 UTCEG score recompute
  7. 2026-09-21 17:55 UTCEG score recompute
  8. 2026-09-21 17:55 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-55473?
CVE-2026-55473 is a medium vulnerability published on September 21, 2026. 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…
When was CVE-2026-55473 disclosed?
CVE-2026-55473 was first published in the National Vulnerability Database on September 21, 2026, with the most recent update on September 23, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55473 actively exploited?
CVE-2026-55473 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 67.1% of all scored CVEs.
What is the CVSS score of CVE-2026-55473?
CVE-2026-55473 has a CVSS v3 base score of 6.0 (NVD).
How do I remediate CVE-2026-55473?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55473, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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