CVE-2026-52773
Received Received - Intake

Stored XSS in YesWiki via Malformed Timestamp Parameter

Vulnerability report for CVE-2026-52773, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-09-05

Last updated on: 2026-09-05

Assigner: GitHub, Inc.

Description

YesWiki is a wiki system written in PHP. From version 4.1.0 to before version 4.6.6, YesWiki's archived-revision view reflects the time GET parameter into a hidden HTML input in handlers/page/show.php without escaping. Because MySQL coerces malformed DATETIME strings, an attacker can append HTML or JavaScript to a valid archived revision timestamp, still load that archived revision, and execute arbitrary JavaScript in the victim's browser. The vulnerable form is only rendered when the victim can both read and edit the target page. In restricted deployments this requires a victim with read and write access to that page. On a default doryphore 4.6.5 install, public pages such as PagePrincipale were editable anonymously during validation, so the issue can also affect unauthenticated visitors in that configuration. This issue has been patched in version 4.6.6.

CVSS Scores

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Meta Information

Published
2026-09-05
Last Modified
2026-09-05
Generated
2026-09-05
AI Q&A
2026-09-05
EPSS Evaluated
N/A
NVD

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
yeswiki yeswiki From 4.1.0 (inc) to 4.6.6 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-80 The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special characters such as "<", ">", and "&" that could be interpreted as web-scripting elements when they are sent to a downstream component that processes web pages.

Attack-Flow Graph

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Executive Summary

YesWiki versions 4.1.0 to 4.6.5 have a reflected XSS vulnerability in the archived-revision view. The time GET parameter is reflected into a hidden HTML input without proper escaping. An attacker can inject malicious JavaScript by manipulating the timestamp, which executes when the victim views the archived revision.

Detection Guidance

To detect this vulnerability, check if your YesWiki instance is running a version between 4.1.0 and 4.6.5. Run the command: grep -r 'YesWiki' /path/to/yeswiki/version.php or check the version in the admin panel. If the version is within this range, the system is vulnerable.

Impact Analysis

An attacker could steal session cookies, perform actions on behalf of the victim, or deface the wiki. The impact depends on user privileges. In default setups, unauthenticated visitors could exploit this if public pages are editable anonymously.

Compliance Impact

This vulnerability could lead to unauthorized data access or modification, violating GDPR (data protection) and HIPAA (health data privacy) requirements for confidentiality and integrity. Organizations may face compliance penalties if exploited.

Mitigation Strategies

Immediately upgrade YesWiki to version 4.6.6 or later. If upgrading is not possible, restrict page editing permissions to trusted users only. Remove anonymous editing rights on public pages to prevent unauthenticated exploitation.

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