Joinmastodon
Vulnerability activity for Joinmastodon: what is being exploited, what was published lately, and when the next patch release is due.
Last 30 days
- CVEs
- 0
- Critical (CVSS 9+)
- 0
- Exploited (CISA KEV)
- 0
- With exploit code
- 0
Last 90 days
- CVEs
- 0
- Critical (CVSS 9+)
- 0
- Exploited (CISA KEV)
- 0
- With exploit code
- 0
Last 365 days
- CVEs
- 13
- Critical (CVSS 9+)
- 0
- Exploited (CISA KEV)
- 0
- With exploit code
- 1
Exploited now
None of this vendor's CVEs are on CISA's known-exploited list.
Recent
- 7.5HighApr 23, 2026Joinmastodon mastodonCVE-2026-41259Mastodon is a free, open-source social network server based on ActivityPub. Prior to v4.5.9, v4.4.16, and v4.3.22, Mastodon allows restricting new user sign-up based on e-mail domain names, and performs basic validation on e-mail addresses, but fails to restrict characters that are interpreted differently by some mailing servers. This vulnerability is fixed in v4.5.9, v4.4.16, and v4.3.22.
- 4.8MediumMar 27, 2026Joinmastodon mastodon Auth bypass / access controlCVE-2026-33869Mastodon is a free, open-source social network server based on ActivityPub. In versions on the 4.5.x branch prior to 4.5.8 and on the 4.4.x branch prior to 4.4.15, an attacker that knows of a quote before it has reached a server can prevent it from being correctly processed on that server. The vulnerability has been patched in Mastodon 4.5.8 and 4.4.15. Mastodon 4.3 and earlier are not affected because they do not support quotes.
- 4.3MediumMar 27, 2026Joinmastodon mastodonCVE-2026-33868Mastodon is a free, open-source social network server based on ActivityPub. Prior to versions 4.5.8, 4.4.15, and 4.3.21, an unauthenticated Open Redirect vulnerability (CWE-601) exists in the `/web/*` route due to improper handling of URL-encoded path segments. An attacker can craft a specially encoded URL that causes the application to redirect users to an arbitrary external domain, enabling phishing attacks and potential OAuth credential theft. The issue occurs because URL-encoded slashes (`%2NucleiDetection
- 5.9MediumFeb 24, 2026Joinmastodon mastodon SSRFCVE-2026-27477Mastodon is a free, open-source social network server based on ActivityPub. FASP registration requires manual approval by an administrator. In versions 4.4.0 through 4.4.13 and 4.5.0 through 4.5.6, an unauthenticated attacker can register a FASP with an attacker-chosen `base_url` that includes or resolves to a local / internal address, leading to the Mastodon server making requests to that address. This only affects Mastodon servers that have opted in to testing the experimental FASP feature by
- 8.2HighFeb 24, 2026Joinmastodon mastodon Auth bypass / access controlCVE-2026-27468Mastodon is a free, open-source social network server based on ActivityPub. FASP registration requires manual approval by an administrator. In versions 4.4.0 through 4.4.13 and 4.5.0 through 4.5.6, actions performed by a FASP to subscribe to account/content lifecycle events or to backfill content did not check properly whether the FASP was actually approved. This only affects Mastodon servers that have opted in to testing the experimental FASP feature by setting the environment variable `EXPERIM
- 6.5MediumFeb 4, 2026Joinmastodon mastodonCVE-2026-25540Mastodon is a free, open-source social network server based on ActivityPub. Prior to versions 4.3.19, 4.4.13, 4.5.6, Mastodon is vulnerable to web cache poisoning via `Rails.cache. When AUTHORIZED_FETCH is enabled, the ActivityPub endpoints for pinned posts and featured hashtags have contents that depend on the account that signed the HTTP request. However, these contents are stored in an internal cache and reused with no regards to the signing actor. As a result, an empty response generated for
- 6.5MediumJan 22, 2026Joinmastodon mastodon Auth bypass / access controlCVE-2026-23964Mastodon is a free, open-source social network server based on ActivityPub. Prior to versions 4.5.5, 4.4.12, and 4.3.18, an insecure direct object reference in the web push subscription update endpoint lets any authenticated user update another user's push subscription by guessing or obtaining the numeric subscription id. This can be used to disrupt push notifications for other users and also leaks the web push subscription endpoint. Any user with a web push subscription is impacted, because ano
- 4.3MediumJan 22, 2026Joinmastodon mastodon Denial of serviceCVE-2026-23963Mastodon is a free, open-source social network server based on ActivityPub. Prior to versions 4.5.5, 4.4.12, and 4.3.18, the server does not enforce a maximum length for the names of lists or filters, or for filter keywords, allowing any user to set an arbitrarily long string as the name or keyword. Any local user can abuse the list or filter fields to cause disproportionate storage and computing resource usage. They can additionally cause their own web interface to be unusable, although they mu
- 7.5HighJan 22, 2026Joinmastodon mastodon Denial of serviceCVE-2026-23962Mastodon is a free, open-source social network server based on ActivityPub. Mastodon versions before v4.3.18, v4.4.12, and v4.5.5 do not have a limit on the maximum number of poll options for remote posts, allowing attackers to create polls with a very large amount of options, greatly increasing resource consumption. Depending on the number of poll options, an attacker can cause disproportionate resource usage in both Mastodon servers and clients, potentially causing Denial of Service either ser
- 5.3MediumJan 22, 2026Joinmastodon mastodon Auth bypass / access controlCVE-2026-23961Mastodon 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. Additi
- 6.5MediumJan 8, 2026Joinmastodon mastodon Information disclosureCVE-2026-22246Mastodon 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 seve
- 7.5HighJan 8, 2026Joinmastodon mastodon SSRFCVE-2026-22245Mastodon is a free, open-source social network server based on ActivityPub. By nature, Mastodon performs a lot of outbound requests to user-provided domains. Mastodon, however, has some protection mechanism to disallow requests to local IP addresses (unless specified in `ALLOWED_PRIVATE_ADDRESSES`) to avoid the "confused deputy" problem. The list of disallowed IP address ranges was lacking some IP address ranges that can be used to reach local IP addresses. An attacker can use an IP address in t
- 3.7LowDec 10, 2025Joinmastodon mastodonCVE-2025-67500Mastodon is a free, open-source social network server based on ActivityPub. Versions 4.2.27 and prior, 4.3.0-beta.1 through 4.3.14, 4.4.0-beta.1 through 4.4.9, 4.5.0-beta.1 through 4.5.2 have discrepancies in error handling which allow checking whether a given status exists by sending a request with a non-English Accept-Language header. Using this behavior, an attacker who knows the identifier of a particular status they are not allowed to see can confirm whether this status exists or not. This
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- mastodon13 CVEs in the last year
Counts cover CVEs and advisories Watch Floor tracks, by the date they became news. Updated every 10 minutes.