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Fencer Vulns
high 8.2

CVE-2024-37903 json

Mastodon has improper authorship check on audience extension for existing posts

published 2024-07-05 2 y ago modified 2026-09-08 2 mo ago also BIT-mastodon-2024-37903 , EUVD-2024-36876 , GHSA-xjvf-fm67-4qc3

cvss
8.2
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 45%
public exploits
0
none known

Summary

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.

Patch / fix

  • bitnami mastodon 4.1.18, 4.2.10
  • joinmastodon mastodon 4.1.18, 4.2.10

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.53% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
OSV 3.1 8.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N

Affected packages

ecosystem package affected fixed in
bitnami mastodon
>=2.6.0, <4.1.18
>=4.2.0, <4.2.10
4.1.18
4.2.10

Affected products

  • mastodon mastodon
  • joinmastodon mastodon

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.