CVE-2026-22246Network attack vector

Authenticated relationship disclosure via unscoped event lookup

Published Jan 8, 2026 · Updated Jan 8, 2026

Authorization bypass in Mastodon's severed-relationship downloads allows remote authenticated users to read other users' lost follows. SeveredRelationshipsController resolves an attacker-supplied event ID with an unscoped find instead of filtering events to current_account. Any registered local account can enumerate events and download CSV lists of lost followers and followed accounts, but the response omits the affected account's name.

CVSS severity6.5
Medium
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authorization bypass in Mastodon's severed-relationship downloads allows remote authenticated users to read other users' lost follows. SeveredRelationshipsController resolves an attacker-supplied event ID with an unscoped find instead of filtering events to current_account. Any registered local account can enumerate events and download CSV lists of lost followers and followed accounts, but the response omits the affected account's name.

The record

CVE
CVE-2026-22246
Published
Jan 8, 2026
Updated
Jan 8, 2026
Vendor
Mastodon
Product
Mastodon
Classifications
CWE-201, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 8, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 4.3.17
  2. Affected versionversion=>= 4.4.0-beta.1, < 4.4.11
  3. Affected versionversion=>= 4.5.0-beta.1, < 4.5.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Mastodon · Mastodonversion=< 4.3.17; version=>= 4.4.0-beta.1, < 4.4.11; version=>= 4.5.0-beta.1, < 4.5.4

Published CVSS scores

6.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
4.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-201Insertion of Sensitive Information Into Sent Data
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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