CVE-2026-77606: Mediawiki/semantic media wiki Ask Plain Table Headers Vulnerability

MODERATE
Advisory Identifier: GHSA-3jp5-3h47-28qf
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CVSS 6.1
CWE-79
Published
Advisory Summary

CVE-2026-77606 is a MODERATE (CVSS 6.1) ask plain table headers vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Mediawiki/semantic media wiki libraries in the Packagist ecosystem. The issue involves ask plain table headers. Remediation is available by upgrading affected packages to version 7.2.0.

CVE-2026-77606 at a Glance

CVE Identifier CVE-2026-77606
GHSA Identifier GHSA-3jp5-3h47-28qf
Severity MODERATE
CVSS v3.1 Base Score 6.1
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product Mediawiki/semantic media wiki
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 6.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction Required (UI:R)
Scope Changed (S:C)
Confidentiality Low (C:L)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2026-77606

To remediate this vulnerability, upgrade all affected Mediawiki/semantic media wiki dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

mediawiki/semantic-media-wiki fixed: 7.2.0 
Upgrade mediawiki/semantic-media-wiki to 7.2.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for mediawiki/semantic-media-wiki

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-77606, inspect your project dependencies for Mediawiki/semantic media wiki:

inspect dependencies for mediawiki/semantic-media-wiki

Analyze the terminal output to locate any version of Mediawiki/semantic media wiki in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 7.2.0), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), where the product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. In Mediawiki/semantic media wiki, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

#### Failure mode When `headers=plain`, table header text was emitted into `<th>` via a raw HTML path. User-controlled `mainlabel` content could therefore become executable HTML. #### Remediation - `TableResultPrinter` now applies output-context escaping before passing plain headers to the table renderer. - The fix is limited to the HTML/plain-header branch so safe rendering modes are unaffected. #### Why this is the right layer The header value is not a structural token; it is display data. Sanitizing it at the sink is correct because the renderer owns the final HTML emission.

CVE-2026-77606 Affected Mediawiki/semantic media wiki Versions

1 component(s)
Fixed Versions:
7.2.0
Product / Package Ecosystem Affected Versions Fixed Version
mediawiki/semantic-media-wiki
 Packagist
< 7.2.0
7.2.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/SemanticMediaWiki/SemanticMediaWiki/security/advisories/GHSA-3jp5-3h47-28qf
Mediawiki/semantic media wiki Source Repository REPOSITORY
https://github.com/SemanticMediaWiki/SemanticMediaWiki
Mediawiki/semantic media wiki Release RELEASE
https://github.com/SemanticMediaWiki/SemanticMediaWiki/releases/tag/7.2.0

Frequently Asked Questions

What is CVE-2026-77606?
CVE-2026-77606 is a security vulnerability in Mediawiki/semantic media wiki involving Ask plain table headers under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Mediawiki/semantic media wiki versions are affected?
Affected versions include releases prior to 7.2.0 across affected packages: mediawiki/semantic-media-wiki.
What version fixes CVE-2026-77606?
Upgrading to 7.2.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is mediawiki/semantic-media-wiki affected?
Yes, mediawiki/semantic-media-wiki is affected in releases prior to 7.2.0. Upgrade your dependency to 7.2.0 or later.
What is the CVSS score of CVE-2026-77606?
CVE-2026-77606 has a CVSS v3.1 base score of 6.1 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
What CWE is associated with CVE-2026-77606?
CVE-2026-77606 is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.).
How can I check Packagist dependencies for CVE-2026-77606?
Run the dependency tree command: 'inspect dependencies for mediawiki/semantic-media-wiki'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-3jp5-3h47-28qf",
  "modified" : "2026-09-18T16:40:36Z",
  "published" : "2026-09-18T16:40:36Z",
  "aliases" : [ "CVE-2026-77606" ],
  "summary" : "Semantic MediaWiki has reflected XSS in Special:Ask plain table headers",
  "details" : "#### Failure mode\n\nWhen `headers=plain`, table header text was emitted into `<th>` via a raw HTML path. User-controlled `mainlabel` content could therefore become executable HTML.\n\n#### Remediation\n\n- `TableResultPrinter` now applies output-context escaping before passing plain headers to the table renderer.\n- The fix is limited to the HTML/plain-header branch so safe rendering modes are unaffected.\n\n#### Why this is the right layer\n\nThe header value is not a structural token; it is display data. Sanitizing it at the sink is correct because the renderer owns the final HTML emission.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "mediawiki/semantic-media-wiki"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "7.2.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 7.1.0"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/SemanticMediaWiki/SemanticMediaWiki/security/advisories/GHSA-3jp5-3h47-28qf"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/SemanticMediaWiki/SemanticMediaWiki"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/SemanticMediaWiki/SemanticMediaWiki/releases/tag/7.2.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-09-18T16:40:36Z",
    "nvd_published_at" : null
  }
}