SB2026042380 - Cross-site scripting in Mastodon

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Main Vulnerability Database SB2026042380

SB2026042380 - Cross-site scripting in Mastodon

Published: April 23, 2026

Security Bulletin ID SB2026042380
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Data manipulation

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Cross-site scripting (CVE-ID: N/A)

CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to conduct cross-site scripting attacks.

The vulnerability exists due to improper neutralization of input during web page generation in user-facing URLs for remote accounts, posts, and media attachments when handling remote object data. A remote attacker can supply a crafted user-facing URL to conduct cross-site scripting attacks.

Exploitation is limited to third-party clients and servers that strip the Content-Security-Policy header.


Remediation

Install update from vendor's website.

References