CVE-2024-25636
Lack of media type verification of Activity Streams objects allows impersonation and takeover of remote accounts
Misskey is an open source, decentralized social media platform with ActivityPub support. Prior to version 2024.2.0, when fetching remote Activity Streams objects, Misskey doesn't check that the response from the remote server has a Content-Type header value of the Activity Streams media type, which allows a threat actor to upload a crafted Activity Streams document to a remote server and make a Misskey instance fetch it, if the remote server accepts arbitrary user uploads. The vulnerability allows a threat actor to impersonate and take over an account on a remote server that satisfies all of the following properties: allows the threat actor to register an account; accepts arbitrary user-uploaded documents and places them on the same domain as legitimate Activity Streams actors; and serves user-uploaded document in response to requests with an Accept header value of the Activity Streams media type. Version 2024.2.0 contains a patch for the issue.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
7.1
Lack of media type verification of Activity Streams objects allows impersonation and takeover of remote accounts
Misskey is an open source, decentralized social media platform with ActivityPub support. Prior to version 2024.2.0, when fetching remote Activity Streams objects, Misskey doesn't check that the response from the remote server has a Content-Type header value of the Activity Streams media type, which allows a threat actor to upload a crafted Activity Streams document to a remote server and make a Misskey instance fetch it, if the remote server accepts arbitrary user uploads. The vulnerability allows a threat actor to impersonate and take over an account on a remote server that satisfies all of the following properties: allows the threat actor to register an account; accepts arbitrary user-uploaded documents and places them on the same domain as legitimate Activity Streams actors; and serves user-uploaded document in response to requests with an Accept header value of the Activity Streams media type. Version 2024.2.0 contains a patch for the issue.
- Record
CVE-2024-25636- CVSS 3.1
- 7.1 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N - Weakness
- CWE-434
- Updated
- 2026-11-02
EUVDEUVD-2024-22954
7.1
Misskey is an open source, decentralized social media platform with ActivityPub support. Prior to version 2024.2.0, when fetching remote Activity Streams objects, Misskey doesn't check that the response from the remote server has a Content-Type header value of the Activity Streams media type, which allows a threat actor to upload a crafted Activity Streams document to a remote server and make a Misskey instance fetch it, if the remote server accepts arbitrary user uploads. The vulnerability allows a threat actor to impersonate and take over an account on a remote server that satisfies all of the following properties: allows the threat actor to register an account; accepts arbitrary user-uploaded documents and places them on the same domain as legitimate Activity Streams actors; and serves user-uploaded document in response to requests with an Accept header value of the Activity Streams media type. Version 2024.2.0 contains a patch for the issue.
- Record
EUVD-2024-22954- CVSS 3.1
- 7.1 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N - Updated
- 2026-11-03
NVD
7.1
Misskey is an open source, decentralized social media platform with ActivityPub support. Prior to version 2024.2.0, when fetching remote Activity Streams objects, Misskey doesn't check that the response from the remote server has a Content-Type header value of the Activity Streams media type, which allows a threat actor to upload a crafted Activity Streams document to a remote server and make a Misskey instance fetch it, if the remote server accepts arbitrary user uploads. The vulnerability allows a threat actor to impersonate and take over an account on a remote server that satisfies all of the following properties: allows the threat actor to register an account; accepts arbitrary user-uploaded documents and places them on the same domain as legitimate Activity Streams actors; and serves user-uploaded document in response to requests with an Accept header value of the Activity Streams media type. Version 2024.2.0 contains a patch for the issue.
- Record
CVE-2024-25636- CVSS 3.1
- 7.1 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N - CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-434
- Updated
- 2026-11-02
OSV
7.1
Lack of media type verification of Activity Streams objects allows impersonation and takeover of remote accounts
Misskey is an open source, decentralized social media platform with ActivityPub support. Prior to version 2024.2.0, when fetching remote Activity Streams objects, Misskey doesn't check that the response from the remote server has a Content-Type header value of the Activity Streams media type, which allows a threat actor to upload a crafted Activity Streams document to a remote server and make a Misskey instance fetch it, if the remote server accepts arbitrary user uploads. The vulnerability allows a threat actor to impersonate and take over an account on a remote server that satisfies all of the following properties: allows the threat actor to register an account; accepts arbitrary user-uploaded documents and places them on the same domain as legitimate Activity Streams actors; and serves user-uploaded document in response to requests with an Accept header value of the Activity Streams media type. Version 2024.2.0 contains a patch for the issue.
- Record
CVE-2024-25636- CVSS 3.1
- 7.1 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N - Weakness
- CWE-434
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, published | EUVD | |
| first indexed | CVE List, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2024-25636 is a high vulnerability (CVSS 7.1) in Misskey, published February 19, 2024. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.66%, the 51st percentile. No source names a fixed version.
References
github.com/misskey-dev/misskey/security/advisories/GHSA-qqrm-9grj-6v32
github.com/misskey-dev/misskey/commit/9a70ce8f5ea9df00001894809f5ce7bc69b14c8a
github.com/misskey-dev/misskey/blob/2024.2.0-beta.10/packages/backend/src/core/activitypub/ApResolverService.ts
github.com/misskey-dev/misskey/blob/2024.2.0-beta.10/packages/backend/src/core/activitypub/models/ApNoteService.ts
github.com/misskey-dev/misskey/blob/2024.2.0-beta.10/packages/backend/src/server/api/endpoints/ap/show.ts
github.com/CVEProject/cvelistV5/tree/main/cves/2024/25xxx/CVE-2024-25636.json
nvd.nist.gov/vuln/detail/CVE-2024-25636