CVE•Published 2026-06-24•Modified 2026-06-25•0 articles on news•5 live references•NVD data

CVE-2026-50128

Vulnerability data via NVD (ingested)

CVSS v3.1

5.3

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

EPSS percentile

Exploit Prediction Scoring System · top 98% of all CVEs

Weaknesses (CWE)

CWE-354Improper Validation of Integrity Check Value

Description

Mastodon is a free, open-source social network server based on ActivityPub. From 4.3.0 until 4.5.11 and 4.4.18, Mastodon has a feature to let websites credit authors of their articles. To prevent false attribution claims, Mastodon uses the attributionDomains JSON-LD term, however, an error in how it is defined makes Linked Data Signatures on the toot:attributionDomains property ineffective. An attacker can arbitrarily modify the attributionDomains value of a legitimately signed Update activity and bypass Mastodon’s signature verification. This vulnerability is fixed in 4.5.11 and 4.4.18.

Timeline

Published 2026-06-24

Modified 2026-06-25

External references

NVD MITRE Exploit-DB GitHub PoC VulnCheck

Search for exposed instances

Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common).

Shodan · vuln tag0 hosts

vuln:CVE-2026-50128

Hosts Shodan has explicitly fingerprinted as vulnerable.

More intel sources (5)

Shodan report

vuln:CVE-2026-50128

Country / ASN / product breakdown for the vuln query.

Censys

vulnerabilities.cve_id: CVE-2026-50128

Censys host search filtered to this CVE id.

grep.app

CVE-2026-50128