CVE intelligence and bounded remediation

CVE-2020-35475 — In MediaWiki before 1.35.1, the messages userrights-expiry-current and userrights-expiry-none can contain raw HTML

High CVSS 7.5

In MediaWiki before 1.35.1, the messages userrights-expiry-current and userrights-expiry-none can contain raw HTML. XSS can happen when a user visits Special:UserRights but does not have rights to change all userrights, and the table on the left side has unchangeable groups in it. (The right column with the changeable groups is not affected and is escaped correctly.)

Severity
High
CVSS
7.5 (3.1)
Published
2020-12-18
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-79

Affected products

  • mediawiki / mediawiki
  • debian / debian_linux / 10.0
  • fedoraproject / fedora / 33

Matched remediation archetype

Cross-site scripting and unsafe browser output

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Trace reflected, stored, and DOM-derived untrusted values into HTML, attributes, URLs, styles, scripts, and client-side template sinks.
  • Identify affected origins, authenticated user roles, sensitive browser capabilities, and where content is shared across tenants.
  • Review framework escaping, rich-text sanitization, legacy templates, and client-side rendering paths.

Remediate safely

  • Use context-aware framework output encoding and safe DOM APIs; keep untrusted data out of executable contexts.
  • Sanitize intentionally supported markup with a maintained allowlist policy and validate URLs and attributes separately.
  • Update affected rendering components and add tests for every output context using inert sentinel markup.

Authoritative sources

Complete CVE record and remediation plan

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