CVE-2026-72916

MEDIUMPre-NVD 6.36.3
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

This medium-severity CVE scores 6.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 1.0% (62nd percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source

Also known asEUVD-2026-55839 (ENISA EUVD)Source: ENISA EUVD

6.3EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 1.0%CVSS: 6.3Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.4.21, 4.5.14, 4.6.4, and 4.7.0-beta.1, PrivateAddressCheck.private_address? in app/lib/private_address_check.rb normalized IPv4-mapped IPv6 addresses but did not recognize IPv4-compatible IPv6 addresses with IPAddr#ipv4_compat?. An attacker could supply an address in the omitted range to bypass the ALLOWED_PRIVATE_ADDRESSES protection and make Mastodon send HTTP requests to loopback interfaces, potentially accessing private resources and services. Exploitation requires a system that supports the obsolete IPv4-compatible IPv6 mechanism. This issue is fixed in versions 4.4.21, 4.5.14, 4.6.4, and 4.7.0-beta.1.

CVSS
6.3
EG Score
6.3MEDIUMmedium confidence
EG Risk
29
EG Risk 29/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity63% × 45%
Impact severity (EG Severity): CVSS 6.3 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.6% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
1.0%
EPSS %ILE
62nd
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (6.3): severity, escalated by confirmed exploitation. This CVE's 6.3 is its impact severity (EG Severity), not escalated.

EG Severity
6.3 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source
EG Likelihood
1.0% within 30 daysSource: FIRST EPSS. FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

August 10, 2026

Last Modified

September 9, 2026

Advisory Details (9)

Auto-updated Aug 10, 2026
Patch available. Sources: github, github_commit, github_release.
GitHub release Patch Available

v4.7.0-beta.1

Patch available: mastodon/mastodon v4.7.0-beta.1 (pre-release)

https://github.com/mastodon/mastodon/releases/tag/v4.7.0-beta.1
GitHub release Patch Available

v4.6.4

Patch available: mastodon/mastodon v4.6.4

https://github.com/mastodon/mastodon/releases/tag/v4.6.4
GitHub release Patch Available

v4.5.14

Patch available: mastodon/mastodon v4.5.14

https://github.com/mastodon/mastodon/releases/tag/v4.5.14
GitHub release Patch Available

v4.4.21

Patch available: mastodon/mastodon v4.4.21

https://github.com/mastodon/mastodon/releases/tag/v4.4.21
GitHub commit Patch Available

commit da47a1bd3cd0 (mastodon/mastodon)

Patch available: mastodon/mastodon v4.4.21 (contains commit da47a1bd3cd0)

https://github.com/mastodon/mastodon/commit/da47a1bd3cd07935d7ca55a1f4f1a76f7f167e0d
GitHub commit Patch Available

commit 930aa9fee26b (mastodon/mastodon)

Patch available: mastodon/mastodon v4.6.4 (contains commit 930aa9fee26b)

https://github.com/mastodon/mastodon/commit/930aa9fee26bf9eaefe27826fa1061288d83373b
GitHub commit

commit 467c933459c7 (mastodon/mastodon)

Fix landed in mastodon/mastodon commit 467c933459c7 — awaiting tagged release

https://github.com/mastodon/mastodon/commit/467c933459c7d0e5513475b9e4888afaedfb1074
GitHub commit Patch Available

commit 18c61f286f1f (mastodon/mastodon)

Patch available: mastodon/mastodon v4.5.14 (contains commit 18c61f286f1f)

https://github.com/mastodon/mastodon/commit/18c61f286f1f5718a8f517940ba384866ffa3892
GitHub advisoryMentions a patch (unverified)

SSRF Protection Bypass via IPv4-compatible IPv6 Addresses · Advisory · mastodon/mastodon · GitHub

https://github.com/mastodon/mastodon/security/advisories/GHSA-vwhj-3g83-v276

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 31× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed its CVE.org record (CNA or CISA ADP). An arrow marks a change the record states ("CVSS → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

Showing the most recent 100 of 143 rows on record for this CVE, as 99 entries (1 repeat merged).

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 1 repeat row among the latest 100 is merged into the row it repeats. The 43 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-13 16:57 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  2. 2026-11-12 16:34 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  3. 2026-11-11 16:40 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  4. 2026-11-10 16:45 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  5. 2026-11-09 16:36 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  6. 2026-11-08 16:40 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  7. 2026-11-07 16:39 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  8. 2026-11-06 16:39 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  9. 2026-11-05 16:38 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  10. 2026-11-04 16:36 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  11. 2026-11-03 16:49 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  12. 2026-11-02 16:46 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  13. 2026-11-01 16:35 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  14. 2026-10-31 16:33 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  15. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.6% · 48th percentile
  16. 2026-10-30 06:55 UTCOSV refresh
  17. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  18. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  19. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  20. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  21. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  22. 2026-10-25 14:06 UTCEchelonGraph re-scored
  23. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  24. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  25. 2026-10-22 19:21 UTCEchelonGraph re-scored
Show 74 more
  1. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  2. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  3. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  4. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  5. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  6. 2026-10-18 03:15 UTCEchelonGraph re-scored
  7. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  8. 2026-10-16 16:44 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  9. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  10. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  11. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  12. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  13. 2026-10-12 15:41 UTCEchelonGraph re-scored
  14. 2026-10-11 19:27 UTCEchelonGraph re-scored
  15. 2026-10-11 16:42 UTCEchelonGraph re-scored
  16. 2026-10-11 14:02 UTCEchelonGraph re-scored
  17. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  18. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  19. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  20. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  21. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  22. 2026-10-06 18:17 UTCEchelonGraph re-scored
  23. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  24. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  25. 2026-10-04 23:58 UTCEchelonGraph re-scored
  26. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  27. 2026-10-03 21:47 UTCEchelonGraph re-scored
  28. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  29. 2026-10-02 09:16 UTCEchelonGraph re-scored
  30. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  31. 2026-09-30 22:24 UTCEchelonGraph re-scored
  32. 2026-09-29 15:24 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  33. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  34. 2026-09-28 13:15 UTCEchelonGraph re-scored
  35. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  36. 2026-09-27 11:05 UTCEchelonGraph re-scored
  37. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  38. 2026-09-25 07:35 UTCEchelonGraph re-scored
  39. 2026-09-24 05:25 UTCEchelonGraph re-scored
  40. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  41. 2026-09-23 03:04 UTCEchelonGraph re-scored
  42. 2026-09-22 00:54 UTCEchelonGraph re-scored
  43. 2026-09-21 21:09 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  44. 2026-09-20 22:43 UTCEchelonGraph re-scored
  45. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  46. 2026-09-19 19:55 UTCEchelonGraph re-scored
  47. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  48. 2026-09-18 17:15 UTCEchelonGraph re-scored
  49. 2026-09-17 14:52 UTCEchelonGraph re-scored
  50. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  51. 2026-09-16 11:55 UTCEchelonGraph re-scored
  52. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  53. 2026-09-15 09:45 UTCEchelonGraph re-scored
  54. 2026-09-15 03:12 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  55. 2026-09-14 07:34 UTCEchelonGraph re-scored
  56. 2026-09-13 05:24 UTCEchelonGraph re-scored
  57. 2026-09-12 15:02 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  58. 2026-09-12 03:14 UTCEchelonGraph re-scored
  59. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  60. 2026-09-11 01:00 UTCEchelonGraph re-scored
  61. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  62. 2026-09-09 05:49 UTCEchelonGraph re-scored
  63. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  64. 2026-09-07 17:10 UTCEchelonGraph re-scored
  65. 2026-09-06 13:48 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  66. 2026-09-06 12:40 UTCEchelonGraph re-scored
  67. 2026-09-05 10:30 UTCEchelonGraph re-scored
  68. 2026-09-04 08:20 UTCEchelonGraph re-scored
  69. 2026-09-04 05:07 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  70. 2026-09-03 02:54 UTCEchelonGraph re-scored
  71. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  72. 2026-09-02 00:44 UTCEchelonGraph re-scored
  73. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  74. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.4% · 28th percentile

Frequently asked(5)

What is CVE-2026-72916?
CVE-2026-72916 is a medium-severity vulnerability; its CVE record was published on August 10, 2026. Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.4.21, 4.5.14, 4.6.4, and 4.7.0-beta.1, PrivateAddressCheck.private_address? in app/lib/private_address_check.rb normalized IPv4-mapped IPv6 addresses but did not recognize IPv4-compatible IPv6 addresses with…
When was the CVE record for CVE-2026-72916 published?
The CVE record for CVE-2026-72916 was published on August 10, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 9, 2026; the record at its source may have been updated since.
Is CVE-2026-72916 actively exploited?
CVE-2026-72916 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.0% probability of exploitation in the next 30 days (62nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-72916?
CVE-2026-72916 has a CVSS base score of 6.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-72916?
A fix for CVE-2026-72916 is available: update to the fixed version the vendor names in its advisory.

Dependency Blast Radius

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