CVE-2026-34598: YesWiki stored XSS in form title field

CVE-2026-34598 · Severity: high · CVSS 6.1 · Published 2026-04-02

YesWiki, a PHP-based wiki system, contains a security flaw that allows attackers to inject malicious scripts into form titles. Because these scripts are saved in the database, they automatically run in the browser of any user who views the affected page. This could lead to unauthorized actions being performed on behalf of users, including administrators, or the theft of sensitive session information.

Technologies: yeswiki/yeswiki (Packagist), YesWiki. Vendors: Packagist, YesWiki.

Quick answers

Is CVE-2026-34598 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-34598 being exploited in the wild.
How severe is CVE-2026-34598?
High severity, with a CVSS score of 6.1, published 2 April 2026.
Which products and versions are affected?
yeswiki/yeswiki (Packagist) < 4.6.0, ECOSYSTEM:introduced=0,fixed=4.6.0; YesWiki < 4.6.0.
Is there a fix for CVE-2026-34598?
Yes. yeswiki/yeswiki (Packagist): upgrade to 4.6.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-34598 attacked?
It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-34598?
Check whether you run yeswiki/yeswiki (Packagist) or YesWiki at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • yeswiki/yeswiki (Packagist): upgrade to 4.6.0 or later
    composer require yeswiki/yeswiki:^4.6.0

Technical details

A stored and blind Cross-Site Scripting (XSS) vulnerability exists in YesWiki prior to version 4.6.0. The root cause is improper neutralization of user-controllable input in the form title field (specifically within the BazaR component). An unauthenticated attacker can submit a malicious JavaScript payload via the 'Name of the event' or 'Description' fields when creating a record. This payload is stored in the backend database and executed whenever a user, including those with administrative privileges, visits the page displaying the record (e.g., via the 'consulter' view). This can lead to session hijacking or unauthorized data access. The issue is addressed in version 4.6.0.

Affected products

  • YesWiki YesWiki < 4.6.0

Identifiers

  • CVE-2026-34598
  • GHSA-37fq-47qj-6j5j

Timeline

  • 2026-03-20: patched: Version 4.6.0 released.
  • 2026-03-29: advisory: GitHub Security Advisory published.
  • 2026-04-02: disclosed: CVE published to NVD.

References

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