Is CVE-2026-52778 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-52778 being exploited in the wild.

How severe is CVE-2026-52778?

Critical severity, with a CVSS score of 9.8, published 8 June 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-2026-52778?

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-2026-52778 attacked?

It is attacked over the network, in a web application.

Am I affected by CVE-2026-52778?

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.

CVE-2026-52778: YesWiki code injection and ReDoS in Bazar form field calculator

Q: Is there a fix for CVE-2026-52778?

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.

Q: How is CVE-2026-52778 attacked?

It is attacked over the network, in a web application.

Q: Am I affected by CVE-2026-52778?

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.

CVE-2026-52778 · Severity: critical · CVSS 9.8 · Published 2026-06-08

YesWiki, a collaborative wiki platform, contains a security flaw in its Bazar form field calculator. This component allows users to create mathematical formulas, but it fails to safely process these inputs. An attacker can exploit this to either crash the web server, causing a service outage, or execute malicious commands to steal sensitive data and take control of the system.

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

Quick answers

Is CVE-2026-52778 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-52778 being exploited in the wild.
How severe is CVE-2026-52778?: Critical severity, with a CVSS score of 9.8, published 8 June 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-2026-52778?: 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-2026-52778 attacked?: It is attacked over the network, in a web application.
Am I affected by CVE-2026-52778?: 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
```
composer require yeswiki/yeswiki:^4.6.6
```

Technical details

A code injection vulnerability exists in YesWiki's Bazar form field calculator (CalcField.php) within the formatValuesBeforeSave method. The application uses a complex recursive regular expression to validate user-defined formulas before passing them to the PHP eval() function. This implementation is susceptible to Regular Expression Denial of Service (ReDoS) via stack overflow in the PCRE engine, leading to a segmentation fault and service crash. Furthermore, if the regex validation is bypassed, an attacker can achieve arbitrary PHP code execution with the privileges of the web server user. The vulnerability is patched in version 4.6.6 by replacing eval() with a safer parsing mechanism.

Affected products

YesWiki YesWiki < 4.6.6

Identifiers

CVE-2026-52778
GHSA-px5m-h76g-p7p8

Timeline

2026-06-02: patched: Version 4.6.6 released
2026-06-08: advisory: NVD published CVE-2026-52778
2026-07-09: advisory: GitHub Advisory published

References

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