CVE-2026-52778Public exploitNetwork attack vector

Worker crash via recursive formula validation

Published Jun 8, 2026 · Updated Jun 8, 2026

Code injection and ReDoS in YesWiki before 4.6.6 allow remote authenticated users to crash PHP workers via crafted Bazar formulas. CalcField.php's formatValuesBeforeSave method applies a recursive PCRE pattern to a user-defined formula and then passes accepted input to PHP eval(); deeply nested expressions exhaust the process stack. Creating or editing a Bazar form is required for the documented crash, while PHP code execution additionally requires bypassing the regular-expression check.

CVSS severity9.8
Critical
EPSS probability0.56%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Code injection and ReDoS in YesWiki before 4.6.6 allow remote authenticated users to crash PHP workers via crafted Bazar formulas. CalcField.php's formatValuesBeforeSave method applies a recursive PCRE pattern to a user-defined formula and then passes accepted input to PHP eval(); deeply nested expressions exhaust the process stack. Creating or editing a Bazar form is required for the documented crash, while PHP code execution additionally requires bypassing the regular-expression check.

The record

CVE
CVE-2026-52778
Published
Jun 8, 2026
Updated
Jun 8, 2026
Vendor
YesWiki
Product
YesWiki
Classifications
CWE-94, CWE-1333, T1499
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 8, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 4.6.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

YesWiki · YesWikiversion=< 4.6.6

Published CVSS scores

9.8GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')
CWE-1333Inefficient Regular Expression Complexity
T1499Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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