CVE-2026-22246

MEDIUMNVD 4.34.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 4.3 under NVD CVSS v3. 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, nvd
4.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 4.3Exploit: None knownExposed: 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. Mastodon 4.3 added notifications of severed relationships, allowing end-users to inspect the relationships they lost as the result of a moderation action. The code allowing users to download lists of severed relationships for a particular event fails to check the owner of the list before returning the lost relationships. Any registered local user can access the list of lost followers and followed users caused by any severance event, and go through all severance events this way. The leaked information does not include the name of the account which has lost follows and followers. This has been fixed in Mastodon v4.3.17, v4.4.11 and v4.5.4.

CVSS v3
4.3
EG Score
4.3(medium)
EG Risk
19(Track)
EG Risk 19/100SSVC: 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
Severity43% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
18%
KEV
Not listed

Published

January 8, 2026

Last Modified

June 17, 2026

Advisory Details (4)

Auto-updated Aug 9, 2026
Patch available. Sources: github_commit, github.
github Patch Available

Local users can enumerate and access severed relationships of every other local user · Advisory · mastodon/mastodon · GitHub

https://github.com/mastodon/mastodon/security/advisories/GHSA-ww85-x9cp-5v24
github_commit Patch Available

commit c1fb6893c517 (mastodon/mastodon)

Patch available: mastodon/mastodon v4.5.7 (contains commit c1fb6893c517)

https://github.com/mastodon/mastodon/commit/c1fb6893c5175d74c074f6f786d504c8bc610d57
github_commit Patch Available

commit b2bcd34486fd (mastodon/mastodon)

Patch available: mastodon/mastodon v4.3.21 (contains commit b2bcd34486fd)

https://github.com/mastodon/mastodon/commit/b2bcd34486fd6681cc0f30028086ef0f47282adf
github_commit Patch Available

commit 68e30985ca7a (mastodon/mastodon)

Patch available: mastodon/mastodon v4.4.14 (contains commit 68e30985ca7a)

https://github.com/mastodon/mastodon/commit/68e30985ca7afdb89af1b2e9dc962e1993dc8076

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 5× in last 7d / 26× 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.

Showing the most recent 100 of 152 total refreshes for this CVE.

  1. 2026-09-19 06:06 UTCOSV refresh
  2. 2026-09-18 19:27 UTCEPSS rescore
  3. 2026-09-16 14:07 UTCEPSS rescore
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  1. 2026-08-20 22:55 UTCEPSS rescore
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  8. 2026-08-14 15:25 UTCEG score recompute
  9. 2026-08-13 22:00 UTCEPSS rescore
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  13. 2026-08-09 21:01 UTCEG score recompute
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  18. 2026-08-06 06:08 UTCEG score recompute▼ 2.20
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  34. 2026-07-23 11:19 UTCOSV refresh
  35. 2026-07-23 03:06 UTCEG score recompute
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  64. 2026-07-06 06:02 UTCOSV refresh
  65. 2026-07-06 02:23 UTCEPSS rescore
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  72. 2026-06-30 23:22 UTCEPSS rescore
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  74. 2026-06-29 14:06 UTCEPSS rescore
  75. 2026-06-28 14:07 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-22246?
CVE-2026-22246 is a medium vulnerability published on January 8, 2026. Mastodon is a free, open-source social network server based on ActivityPub. Mastodon 4.3 added notifications of severed relationships, allowing end-users to inspect the relationships they lost as the result of a moderation action. The code allowing users to download lists of severed relationships…
When was CVE-2026-22246 disclosed?
CVE-2026-22246 was first published in the National Vulnerability Database on January 8, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-22246 actively exploited?
CVE-2026-22246 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 81.7% of all scored CVEs.
What is the CVSS score of CVE-2026-22246?
CVE-2026-22246 has a CVSS v3 base score of 4.3 (NVD).
How do I remediate CVE-2026-22246?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-22246, 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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