We just released Mastodon 4.6.4, 4.5.14 and 4.4.21.
Those updates include multiple security fixes, including fixes for two major issues.
We encourage server administrators to update as soon as possible, as one of the issues can expose PII of local users. We are investigating potential uses of this exploit and will soon share more information.
Full release notes and update instructions are available on the GitHub release page.
https://github.com/mastodon/mastodon/releases/v4.6.4
#MastoAdmin
Mastodon Engineering
npub1u8…2s78a
2026-07-27 14:37:52 UTC
Author Public Key
npub1u84dwmpv2zerws66094ehfyad0yj7vsh2vrt9k4xecyfutlcmzjq72s78aSeen on
wss://relay.momostr.pinkPublished at
2026-07-27 14:37:52 UTCEvent JSON
{
"id": "791e74b7e0927d6618d6a2965a5ebe0f220a0e54439aa8d387095bec8ab6dd02",
"pubkey": "e1ead76c2c50b237435a796b9ba49d6bc92f32175306b2daa6ce089e2ff8d8a4",
"created_at": 1785163072,
"kind": 1,
"tags": [
[
"t",
"mastoadmin"
],
[
"proxy",
"https://mastodon.social/@MastodonEngineering/116992447094087771",
"web"
],
[
"proxy",
"https://mastodon.social/users/MastodonEngineering/statuses/116992447094087771",
"activitypub"
],
[
"L",
"pink.momostr"
],
[
"l",
"pink.momostr.activitypub:https://mastodon.social/users/MastodonEngineering/statuses/116992447094087771",
"pink.momostr"
],
[
"-"
]
],
"content": "We just released Mastodon 4.6.4, 4.5.14 and 4.4.21.\n\nThose updates include multiple security fixes, including fixes for two major issues.\n\nWe encourage server administrators to update as soon as possible, as one of the issues can expose PII of local users. We are investigating potential uses of this exploit and will soon share more information.\n\nFull release notes and update instructions are available on the GitHub release page.\n\nhttps://github.com/mastodon/mastodon/releases/v4.6.4\n\n#MastoAdmin",
"sig": "018309faab8b45b4569912326252476473ff6dae53708213c2e10ddfa5157cd1ea83444a4c80697715c7b585f2bd76a9dbdc99c3ce88d251fe8974c60a4c56b9"
}