What is CVE-2026-48028?

CVE-2026-48028 is a medium-severity vulnerability in Mastodon, classified under Improper Validation of Integrity Check Value. CVSS score: 6.5/10. Published 2026-06-24.

How severe is CVE-2026-48028?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in Mastodon

CVE-2026-48028

Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.5.10, 4.4.17, and 4.3.23, Mastodon's normalization of incoming activities signed with Linked-Data Signatures does not sufficiently protect the activitie…

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L.

Affected products

Mastodon — versions >= 4.5.0-beta.1, < 4.5.10, >= 4.4.0-beta.1, < 4.4.17, < 4.3.23

Weakness classification (CWE)

CWE-354 — Improper Validation of Integrity Check Value

References

security-advisories@github.com (x_refsource_CONFIRM)

Frequently asked questions

What is CVE-2026-48028?: CVE-2026-48028 is a medium-severity vulnerability in Mastodon, classified under Improper Validation of Integrity Check Value. CVSS score: 6.5/10. Published 2026-06-24.
How severe is CVE-2026-48028?: Medium severity. CVSS v3 base score is 6.5 out of 10.