CVE Feed

    Dashboard / CVE / CVE-2026-23961

    CVE-2026-23961

    Mastodon is a free, open-source social network server based on ActivityPub. Mastodon allows server administrators to suspend remote users to prevent interactions. However, some logic errors allow already-known posts from such suspended users to appear in timelines if boosted. Furthermore, under certain circumstances, previously-unknown posts from suspended users can be processed. This issue allows old posts from suspended users to occasionally end up on timelines on all Mastodon versions. Additionally, on Mastodon versions from v4.5.0 to v4.5.4, v4.4.5 to v4.4.11, v4.3.13 to v4.3.17, and v4.2.26 to v4.2.29, remote suspended users can partially bypass the suspension to get new posts in. Mastodon versions v4.5.5, v4.4.12, v4.3.18 are patched.

    Published:Jan 22, 2026
    Last Modified:Apr 18, 2026
    EPS:Jan 22, 2026
    EPSS Score:0.00019
    CVSS Score:5.3

    Affected Products

    Vendor
    Joinmastodon
    Product
    Mastodon

    Exploits

    No exploit reference

    Common Weakness Enumeration

    CWE-863 Incorrect Authorization

    Common Attack Pattern Enumeration and Classification (CAPEC)

    No CAPEC recorded yet

    Related CVEs

    CVE-2026-59825 (CVSS 7.4) — Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.4.19 and from 4.5.0 unt…
    CVE-2026-72916 (CVSS 6.3) — Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.4.21, 4.5.14, 4.6.4, an…
    CVE-2026-72915 (CVSS 7.5) — Mastodon is a free, open-source social network server based on ActivityPub. From 4.6.0-beta.1 until 4.6.4 and …
    CVE-2026-72914 (CVSS 7.5) — Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.4.21, 4.5.14, 4.6.4, an…
    CVE-2026-50129 (CVSS 7.5) — Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.5.11, 4.4.18, and 4.3.2…
    CVE-2026-50128 (CVSS 5.3) — Mastodon is a free, open-source social network server based on ActivityPub. From 4.3.0 until 4.5.11 and 4.4.18…
    CVE-2026-48028 (CVSS 6.5) — Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.5.10, 4.4.17, and 4.3.2…
    CVE-2026-47389 (CVSS 8.6) — Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.5.10, 4.4.17, and 4.3.2…
    CVE-2026-46349 (CVSS 5.3) — Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.5.10, 4.4.17, and 4.3.2…
    CVE-2026-46348 (CVSS 8.7) — Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.5.10, 4.4.17, and 4.3.2…

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High