Medium

Semantic MediaWiki affected by Special:Ask table `sep` parameter reflected XSS

  • Disclosed: 18.09.2026
  • Updated: 11.10.2026 10:22

Failure mode

sep was inserted verbatim into the HTML that joins a table cell's values. This made it possible to inject HTML through the separator value. The same unsanitised table HTML is produced both for the standard Special:Ask render and for its raw request output (request_type=raw), so the injection was reachable without authentication.

Remediation

  • In all non-wiki output modes (HTML, raw request, file), sep is escaped unless it is a safe <br> variant.
  • This preserves legitimate line-break separators while blocking markup injection.

Maintenance note

If the table renderer ever gains richer separator semantics, keep the whitelist explicit. Do not expand the allowed HTML surface casually.

Affected software

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PlatformPackageVulnerable versionsFixed in
Composer package mediawiki/semantic-media-wiki < 7.2.0 7.2.0

References

CVSS score 6.1/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Weakness (CWE)
CWE-79
Platform
Composer
Package
mediawiki/semantic-media-wiki
Disclosed
18.09.2026
Updated
11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-7xv3-gf2g-498h - CC BY 4.0

Vulnerability history: mediawiki/semantic-media-wiki

All published vulnerabilities of this package (Composer package), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (10) in the archive
Total entries
10
First → latest
12.2023 09.2026
Without a fix
0
Exploited in attacks
0

Severity breakdown

  • High 2
  • Medium 8

Disclosures per year

  1. 2023: 1
  2. 2024: 0
  3. 2025: 0
  4. 2026: 9
Severity:
  1. Semantic MediaWiki affected by Special:Ask table `sep` parameter reflected XSS this entry
    Medium · 6.1 CVE-2026-77607 < 7.2.0 7.2.0

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