CVE-2026-47389

HIGHPre-NVD 8.68.6—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.6 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 86% 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
8.6
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 8.6Exploit: NoneExposed: 0

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

Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.5.10, 4.4.17, and 4.3.23, when using Ruby versions older than 3.4, PrivateAddressCheck.private_address? returns false for IPv4-mapped IPv6 addresses (::ffff:a.b.c.d) corresponding to some private IPv4 addresses, depending on Ruby version, this can include loopback, RFC1918 private networks, and link-local space. An attacker who controls DNS for any domain can publish an AAAA record with such a mapped address; any outbound HTTP fetch Mastodon performs against that hostname then opens a real TCP connection to the underlying IPv4 address, including 127.0.0.1 and cloud-metadata endpoints such as 169.254.169.254. This vulnerability is fixed in 4.5.10, 4.4.17, and 4.3.23.

CVSS v3
8.6
EG Score
8.6(medium)
EPSS
14.0%
KEV
Not listed

Published

June 24, 2026

Last Modified

June 25, 2026

Advisory Details (1)

Auto-updated Jun 24, 2026
Patch available. Sources: github.
github Patch Available

SSRF protection bypass on older Ruby versions (incomplete remediation for GHSA-xfrj-c749-jxxq) · Advisory · mastodon/mastodon · GitHub

https://github.com/mastodon/mastodon/security/advisories/GHSA-xx55-4rrg-8xg6

Weakness Classification(3)

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

Data Freshness Timeline

(refreshed 20× in last 7d / 50× 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. 2026-07-11 20:40 UTCEG score recompute
  2. 2026-07-11 08:27 UTCEPSS rescore
  3. 2026-07-11 07:35 UTCEG score recompute
  4. 2026-07-10 18:29 UTCEG score recompute
  5. 2026-07-10 05:12 UTCEG score recompute
  6. 2026-07-09 19:10 UTCEPSS rescore
  7. 2026-07-09 16:05 UTCEG score recompute
  8. 2026-07-09 02:40 UTCEG score recompute
  9. 2026-07-08 15:16 UTCEPSS rescore
  10. 2026-07-08 13:35 UTCEG score recompute
  11. 2026-07-08 00:28 UTCEG score recompute
  12. 2026-07-07 13:46 UTCEPSS rescore
  13. 2026-07-07 11:23 UTCEG score recompute
  14. 2026-07-06 22:19 UTCEG score recompute
  15. 2026-07-06 16:27 UTCEPSS rescore
  16. 2026-07-06 09:12 UTCEG score recompute
  17. 2026-07-06 02:23 UTCEPSS rescore
  18. 2026-07-05 19:46 UTCEG score recompute
  19. 2026-07-05 06:42 UTCEG score recompute
  20. 2026-07-05 02:30 UTCEPSS rescore
  21. 2026-07-04 17:37 UTCEG score recompute
  22. 2026-07-04 06:31 UTCEPSS rescore
  23. 2026-07-04 04:32 UTCEG score recompute
  24. 2026-07-03 15:21 UTCEG score recompute
  25. 2026-07-03 02:16 UTCEG score recompute
Show 25 more
  1. 2026-07-02 13:11 UTCEG score recompute
  2. 2026-07-02 00:05 UTCEG score recompute
  3. 2026-07-01 15:07 UTCEPSS rescore
  4. 2026-07-01 11:01 UTCEG score recompute
  5. 2026-06-30 23:22 UTCEPSS rescore
  6. 2026-06-30 21:57 UTCEG score recompute
  7. 2026-06-30 08:53 UTCEG score recompute
  8. 2026-06-29 19:49 UTCEG score recompute
  9. 2026-06-29 14:06 UTCEPSS rescore
  10. 2026-06-29 14:06 UTCEPSS rescore
  11. 2026-06-29 06:45 UTCEG score recompute
  12. 2026-06-28 17:41 UTCEG score recompute
  13. 2026-06-28 14:07 UTCEPSS rescore
  14. 2026-06-28 04:56 UTCEPSS rescore
  15. 2026-06-28 04:56 UTCEPSS rescore
  16. 2026-06-28 04:37 UTCEG score recompute
  17. 2026-06-27 15:33 UTCEG score recompute
  18. 2026-06-27 03:08 UTCEPSS rescore
  19. 2026-06-27 02:28 UTCEG score recompute
  20. 2026-06-26 13:24 UTCEG score recompute
  21. 2026-06-26 00:17 UTCEG score recompute
  22. 2026-06-25 13:49 UTCEPSS rescore
  23. 2026-06-25 11:08 UTCEG score recompute
  24. 2026-06-24 22:04 UTCEG score recompute
  25. 2026-06-24 22:03 UTCNVD updatefirst tracked

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Frequently asked(5)

What is CVE-2026-47389?
CVE-2026-47389 is a high vulnerability published on June 24, 2026. Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.5.10, 4.4.17, and 4.3.23, when using Ruby versions older than 3.4, PrivateAddressCheck.private_address? returns false for IPv4-mapped IPv6 addresses (::ffff:a.b.c.d) corresponding to some private IPv4 addresses,…
When was CVE-2026-47389 disclosed?
CVE-2026-47389 was first published in the National Vulnerability Database on June 24, 2026, with the most recent update on June 25, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-47389 actively exploited?
CVE-2026-47389 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 14.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-47389?
CVE-2026-47389 has a CVSS v3 base score of 8.6 (NVD).
How do I remediate CVE-2026-47389?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-47389, 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.

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