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Fencer Intel
medium 6.1

CVE-2026-77610 json

Semantic MediaWiki has a query debug output XSS (`DebugFormatter`)

published last mo. modified last mo. also EUVD-2026-83186 , GHSA-q5fm-9mx6-44f4

cvss
6.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 21%
public exploits
0
none known

Summary

Semantic MediaWiki is a free, open-source extension to MediaWiki that lets users store and query data within the wiki's pages. Prior to version 7.2.0, query debug output (`format=debug`, or the `debug` request parameter on `Special:Ask`) is assembled by `SMW\Query\DebugFormatter` and emitted as raw HTML. Several of its sinks apply no output-context encoding, so attacker-controlled query input is reflected into the page without escaping. On `Special:Ask` the resulting string is concatenated into the page and sent through `OutputPage::addHTML`, never through the MediaWiki parser or Sanitizer. No special user right is required; an anonymous request suffices. This is a reflected XSS: the payload is taken from the request and echoed in the same response. Exploitation requires the query condition to target a text/blob-typed property (whose value is re-serialized verbatim); the predefined `_txt` properties (`Text`, etc.) that ship on every install satisfy this, so no attacker-created content is needed. Version 7.2.0 patches the issue.

Patch / fix

  • packagist mediawiki/semantic-media-wiki 7.2.0
  • semantic-mediawiki semantic_mediawiki 7.2.0

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
last mo.

Exploit prediction

0.28% chance of exploitation in the next 30 days, higher than 21% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
GitHub 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
packagist mediawiki/semantic-media-wiki
<7.2.0
7.2.0

Affected products

  • SemanticMediaWiki SemanticMediaWiki

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.