CVE-2024-37903
Mastodon has improper authorship check on audience extension for existing posts
Mastodon is a self-hosted, federated microblogging platform. Starting in version 2.6.0 and prior to versions 4.1.18 and 4.2.10, by crafting specific activities, an attacker can extend the audience of a post they do not own to other Mastodon users on a target server, thus gaining access to the contents of a post not intended for them. Versions 4.1.18 and 4.2.10 contain a patch for this issue.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
8.2
Mastodon has improper authorship check on audience extension for existing posts
Mastodon is a self-hosted, federated microblogging platform. Starting in version 2.6.0 and prior to versions 4.1.18 and 4.2.10, by crafting specific activities, an attacker can extend the audience of a post they do not own to other Mastodon users on a target server, thus gaining access to the contents of a post not intended for them. Versions 4.1.18 and 4.2.10 contain a patch for this issue.
- Record
CVE-2024-37903- CVSS 3.1
- 8.2 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N - Weakness
- CWE-862
- Updated
- 2026-11-02
EUVDEUVD-2024-36876
8.2
Mastodon is a self-hosted, federated microblogging platform. Starting in version 2.6.0 and prior to versions 4.1.18 and 4.2.10, by crafting specific activities, an attacker can extend the audience of a post they do not own to other Mastodon users on a target server, thus gaining access to the contents of a post not intended for them. Versions 4.1.18 and 4.2.10 contain a patch for this issue.
- Record
EUVD-2024-36876- CVSS 3.1
- 8.2 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N - Updated
- 2026-11-03
NVD
8.2
Mastodon is a self-hosted, federated microblogging platform. Starting in version 2.6.0 and prior to versions 4.1.18 and 4.2.10, by crafting specific activities, an attacker can extend the audience of a post they do not own to other Mastodon users on a target server, thus gaining access to the contents of a post not intended for them. Versions 4.1.18 and 4.2.10 contain a patch for this issue.
- Record
CVE-2024-37903- CVSS 3.1
- 8.2 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N - Weakness
- CWE-862
- Updated
- 2026-11-02
OSV
8.2
Mastodon has improper authorship check on audience extension for existing posts
Mastodon is a self-hosted, federated microblogging platform. Starting in version 2.6.0 and prior to versions 4.1.18 and 4.2.10, by crafting specific activities, an attacker can extend the audience of a post they do not own to other Mastodon users on a target server, thus gaining access to the contents of a post not intended for them. Versions 4.1.18 and 4.2.10 contain a patch for this issue.
- Record
CVE-2024-37903- CVSS 3.1
- 8.2 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N - Weakness
- CWE-862
- Updated
- 2026-11-02
OSVBIT-mastodon-2024-37903 No score
Mastodon has improper authorship check on audience extension for existing posts
Mastodon is a self-hosted, federated microblogging platform. Starting in version 2.6.0 and prior to versions 4.1.18 and 4.2.10, by crafting specific activities, an attacker can extend the audience of a post they do not own to other Mastodon users on a target server, thus gaining access to the contents of a post not intended for them. Versions 4.1.18 and 4.2.10 contain a patch for this issue.
- Record
BIT-mastodon-2024-37903- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
mastodonBitnami |
2.6.0 up to 4.1.18, 4.2.0 up to 4.2.10 | 4.1.184.2.10 |
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-2024-37903 is a high vulnerability (CVSS 8.2) in Joinmastodon Mastodon, published July 5, 2024. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.53%, the 45th percentile. Fixed in mastodon 4.1.18.
References
github.com/mastodon/mastodon/security/advisories/GHSA-xjvf-fm67-4qc3
github.com/mastodon/mastodon/commit/a1c7aae28aecf06659c5b18cfa131b37cd1512a3
github.com/mastodon/mastodon/commit/d4bf22b632ea8b1174375c4966a6768ab66393b6
github.com/mastodon/mastodon/releases/tag/v4.1.18
github.com/mastodon/mastodon/releases/tag/v4.2.10
nvd.nist.gov/vuln/detail/CVE-2024-37903
github.com/CVEProject/cvelistV5/tree/main/cves/2024/37xxx/CVE-2024-37903.json