CVE-2026-34598: Yeswiki/yeswiki Cross-Site Scripting Vulnerability

HIGH
Advisory Identifier: GHSA-37fq-47qj-6j5j
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CWE-87 CWE-79
Published
Advisory Summary

CVE-2026-34598 is a HIGH cross-site scripting vulnerability (CWE-87: Improper Neutralization of Alternate XSS Syntax) affecting Yeswiki/yeswiki libraries in the Packagist ecosystem. The issue involves yeswiki has persistent blind xss at "/?bazar&vue=consulter". Remediation is available by upgrading affected packages to version 4.6.0.

CVE-2026-34598 at a Glance

CVE Identifier CVE-2026-34598
GHSA Identifier GHSA-37fq-47qj-6j5j
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-87: Improper Neutralization of Alternate XSS Syntax
Affected Product Yeswiki/yeswiki
Package Ecosystem Packagist
Published Date
Last Updated

How to Fix CVE-2026-34598

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

yeswiki/yeswiki fixed: 4.6.0 
Upgrade yeswiki/yeswiki to 4.6.0
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 yeswiki/yeswiki

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-34598, inspect your project dependencies for Yeswiki/yeswiki:

inspect dependencies for yeswiki/yeswiki

Analyze the terminal output to locate any version of Yeswiki/yeswiki in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 4.6.0), 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-87: Improper Neutralization of Alternate XSS Syntax, where the product does not neutralize or incorrectly neutralizes user-controlled input for alternate script syntax. In Yeswiki/yeswiki, 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

### Summary A stored and blind XSS vulnerability exists in the form title field. A malicious attacker can inject JavaScript without any authentication via a form title that is saved in the backend database. When any user visits that injected page, the JavaScript payload gets executed. Type: Stored and Blind Cross-Site Scripting (XSS) Affected Component: form title input field Authentication Required: No (Unauthenticated attack possible) Impact: Arbitrary JavaScript execution in victim’s browser ### Details A Stored XSS vulnerability occurs when an application stores malicious user input (in this case, a script injected via the form title field) in its backend database and renders it later on a page viewed by other users without proper sanitization or encoding. In this case, the attacker can inject JavaScript payloads in the title field of a form, which the application stores in the database. When any user, such as an admin or another visitor, views the page that displays this title, the malicious script executes in their browser context. ### PoC - Visit `https://yeswiki.net/?BazaR&vue=formulaire` or `localhost/?BazaR&vue=formulaire` or `https://ferme.yeswiki.net/[username]/?BazaR&vue=formulaire` - Click on the `+` icon to add a record via the `Diary` form. - Inject the payload like: `<script>alert(document.cookie)</script>` or `<script>alert(1)</script>` into `Name of the event` and `Description` - Then save the record by clicking `To validate` - The payload will be executed when anyone visits `/?BazaR&vue=consulter` also in the diary record `/?wiki=BazaR&vue=consulter&action=recherche&q=&id=2&facette=` The payload is persistant.

CVE-2026-34598 Affected Yeswiki/yeswiki Versions

1 component(s)
Fixed Versions:
4.6.0
Product / Package Ecosystem Affected Versions Fixed Version
yeswiki/yeswiki
 Packagist
< 4.6.0
4.6.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/YesWiki/yeswiki/security/advisories/GHSA-37fq-47qj-6j5j
NVD — CVE-2026-34598 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-34598
Yeswiki/yeswiki Source Repository REPOSITORY
https://github.com/YesWiki/yeswiki
Yeswiki/yeswiki Release RELEASE
https://github.com/YesWiki/yeswiki/releases/tag/v4.6.0

Frequently Asked Questions

What is CVE-2026-34598?
CVE-2026-34598 is a security vulnerability in Yeswiki/yeswiki involving YesWiki has Persistent Blind XSS at "/?BazaR&vue=consulter" under CWE-87: Improper Neutralization of Alternate XSS Syntax.
Which Yeswiki/yeswiki versions are affected?
Affected versions include releases prior to 4.6.0 across affected packages: yeswiki/yeswiki.
What version fixes CVE-2026-34598?
Upgrading to 4.6.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is yeswiki/yeswiki affected?
Yes, yeswiki/yeswiki is affected in releases prior to 4.6.0. Upgrade your dependency to 4.6.0 or later.
What CWE is associated with CVE-2026-34598?
CVE-2026-34598 is classified under CWE-87: Improper Neutralization of Alternate XSS Syntax (The product does not neutralize or incorrectly neutralizes user-controlled input for alternate script syntax.).
How can I check Packagist dependencies for CVE-2026-34598?
Run the dependency tree command: 'inspect dependencies for yeswiki/yeswiki'. 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-37fq-47qj-6j5j",
  "modified" : "2026-04-10T19:34:59Z",
  "published" : "2026-04-01T00:13:57Z",
  "aliases" : [ "CVE-2026-34598" ],
  "summary" : "YesWiki has Persistent Blind XSS at \"/?BazaR&vue=consulter\"",
  "details" : "### Summary\nA stored and blind XSS vulnerability exists in the form title field. A malicious attacker can inject JavaScript without any authentication via a form title that is saved in the backend database. When any user visits that injected page, the JavaScript payload gets executed.\n\nType: Stored and Blind Cross-Site Scripting (XSS)\nAffected Component: form title input field\nAuthentication Required: No (Unauthenticated attack possible)\nImpact: Arbitrary JavaScript execution in victim’s browser\n\n\n### Details\nA Stored XSS vulnerability occurs when an application stores malicious user input (in this case, a script injected via the form title field) in its backend database and renders it later on a page viewed by other users without proper sanitization or encoding.\n\nIn this case, the attacker can inject JavaScript payloads in the title field of a form, which the application stores in the database. When any user, such as an admin or another visitor, views the page that displays this title, the malicious script executes in their browser context.\n\n### PoC\n- Visit `https://yeswiki.net/?BazaR&vue=formulaire` or `localhost/?BazaR&vue=formulaire` or \n `https://ferme.yeswiki.net/[username]/?BazaR&vue=formulaire`\n- Click on the `+` icon to add a record via the `Diary` form.\n- Inject the payload like: `<script>alert(document.cookie)</script>` or `<script>alert(1)</script>` into `Name of the event` and `Description`\n- Then save the record by clicking `To validate`\n- The payload will be executed when anyone visits `/?BazaR&vue=consulter` also in the diary record \n`/?wiki=BazaR&vue=consulter&action=recherche&q=&id=2&facette=`\n\nThe payload is persistant.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "yeswiki/yeswiki"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "4.6.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/YesWiki/yeswiki/security/advisories/GHSA-37fq-47qj-6j5j"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-34598"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/YesWiki/yeswiki"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/YesWiki/yeswiki/releases/tag/v4.6.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79", "CWE-87" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-01T00:13:57Z",
    "nvd_published_at" : "2026-04-02T18:16:31Z"
  }
}