# CVE-2026-52777: YesWiki PHP object injection in BazarImportAction

Source: https://junglewise.ai/threats/cve-2026-52777-yeswiki-php-object-injection-in-bazarimportaction  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-05. Updated: 2026-07-09  
License: CC BY 4.0 with a link back

CVE-2026-52777 · Severity: critical · CVSS 4 · Published 2026-09-05

YesWiki, a collaborative wiki platform, is vulnerable to a critical security flaw in its Bazar import tool. An attacker can trick a wiki administrator into visiting a malicious website, which then silently triggers a command on the wiki server. This could allow the attacker to take full control of the server, steal sensitive data, or disrupt the website's operations.

Technologies: [yeswiki/yeswiki (Packagist)](https://junglewise.ai/threats/technologies/yeswiki-yeswiki), [YesWiki](https://junglewise.ai/threats/technologies/yeswiki). Vendors: [Packagist](https://junglewise.ai/threats/vendors/packagist), [YesWiki](https://junglewise.ai/threats/vendors/yeswiki).

## Quick answers

**Is CVE-2026-52777 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-52777 being exploited in the wild.

**How severe is CVE-2026-52777?** Critical severity, with a CVSS score of 4, published 5 September 2026.

**Which products and versions are affected?** yeswiki/yeswiki (Packagist) < 4.6.6, ECOSYSTEM:introduced=0,fixed=4.6.6; YesWiki < 4.6.6.

**Is there a fix for CVE-2026-52777?** Yes. yeswiki/yeswiki (Packagist): upgrade to 4.6.6 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-52777 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-52777?** 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 4.6.6 or later

  ```sh
  composer require yeswiki/yeswiki:^4.6.6
  ```


## Technical details

A PHP Object Injection vulnerability exists in YesWiki's `CSVManager::importEntry` due to the unsafe use of `unserialize()` on user-supplied data from the `importfiche` POST parameter. The vulnerability is reachable via the `bazarimport` action. While the action requires administrative privileges, it lacks CSRF protection, allowing a remote attacker to perform a Cross-Site Request Forgery attack against a logged-in administrator. By leveraging existing gadget chains in included libraries like Doctrine, an attacker can achieve Remote Code Execution (RCE). The issue is fixed in version 4.6.6 by restricting allowed classes in `unserialize()` and adding CSRF token validation.

## Affected products

- YesWiki yeswiki < 4.6.6

## Identifiers

- CVE-2026-52777
- GHSA-9369-69wj-7m2f

## Timeline

- 2026-06-02: disclosed
- 2026-07-09: advisory
- 2026-07-09: patched

## References

- [https://api.github.com/users/fg0x0](https://api.github.com/users/fg0x0)
- [https://github.com/fg0x0](https://github.com/fg0x0)
- [https://api.github.com/users/fg0x0/gists%7B/gist_id%7D](https://api.github.com/users/fg0x0/gists%7B/gist_id%7D)
- [https://api.github.com/users/fg0x0/repos](https://api.github.com/users/fg0x0/repos)
- [https://avatars.githubusercontent.com/u/35772301?v=4](https://avatars.githubusercontent.com/u/35772301?v=4)
- [https://api.github.com/users/fg0x0/events%7B/privacy%7D](https://api.github.com/users/fg0x0/events%7B/privacy%7D)

## Related threats

- [YesWiki SQL injection in despam.php INTERVAL operand](https://junglewise.ai/threats/cve-2026-116828-yeswiki-before-4-7-0-contains-a-sql-injection-vulnerability-in)
- [YesWiki server-side request forgery in Bazar CSV import](https://junglewise.ai/threats/cve-2026-116827-yeswiki-before-4-7-0-contains-a-server-side-request-forgery)
- [YesWiki server-side request forgery in DuplicationManager](https://junglewise.ai/threats/cve-2026-116826-yeswiki-before-4-7-0-contains-a-server-side-request-forgery)
- [YesWiki HTTP Signature replay protection missing in ActivityPub inbox](https://junglewise.ai/threats/cve-2026-116825-yeswiki-from-4-6-2-before-4-7-0-lacks-replay-protection-in)
- [YesWiki stored cross-site scripting in referrers_sites handler](https://junglewise.ai/threats/cve-2026-116824-yeswiki-before-4-7-0-contains-a-stored-cross-site-scripting)