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

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.1 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS

• CVE-2026-77607: 0.28% estimated exploitation activity in the next 30 days; percentile 20.87 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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 (requesttype=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.

Published by the source

18 Sep 2026, 16:50 UTC

Last modified by the source

18 Sep 2026, 17:00 UTC

Source last checked

26 Oct 2026, 14:53 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-7xv3-gf2g-498h

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-7xv3-gf2g-498h

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# Patch Next advisory brief: CVE-2026-77607

Advisory: Semantic MediaWiki affected by Special:Ask table `sep` parameter reflected XSS
IDs: CVE-2026-77607, GHSA-7xv3-gf2g-498h
Record: https://patchnext.com/advisories/cve-2026-77607 (revision 2, source checked 26 Oct 2026, 14:53 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: mediawiki/semantic-media-wiki 7.2.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist mediawiki/semantic-media-wiki: affected <= 7.1.0; fixed in 7.2.0

## Suggested inspection (read-only)
- Packagist mediawiki/semantic-media-wiki: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on mediawiki/semantic-media-wiki.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-7xv3-gf2g-498h (OSV record GHSA-7xv3-gf2g-498h lists affected ranges: Packagist mediawiki/semantic-media-wiki >=0 <7.2.0 (fixed))
- Verified: https://github.com/advisories/GHSA-7xv3-gf2g-498h (GitHub-reviewed advisory GHSA-7xv3-gf2g-498h lists affected ranges: Packagist mediawiki/semantic-media-wiki >=0 <=7.1.0)

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