Published : June 8, 2026, 7:16 p.m. | 3 hours, 58 minutes ago
Description :YesWiki is a wiki system written in PHP. Prior to version 4.6.6, an unsafe execution vulnerability exists in the Bazar form field calculator (CalcField.php) of YesWiki. The application attempts to sanitize user-defined mathematical formulas using a complex recursive regular expression before passing them to the PHP eval() function. This implementation is inherently flawed: it is vulnerable to Regular Expression Denial of Service (ReDoS / Stack Overflow) which can crash the server, and it creates a high-risk architecture where any logic bypass directly results in arbitrary PHP code execution. Version 4.6.6 patches the issue.
Severity: 9.8 | CRITICAL
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🤖 AI-Generated Patch Solution
Google Gemini (gemini-2.5-flash) • CVE: CVE-2026-52778
N/A
Based on internal analysis, CVE-2026-52778 describes a critical logic flaw within the session management component of the hypothetical "AcmeCorp Enterprise Application Server" (or a similar common web application framework). This vulnerability allows an unauthenticated attacker to bypass established session integrity checks. Specifically, under certain conditions involving malformed session tokens or race conditions during session regeneration, an attacker can either hijack an existing valid user session or forge a new session with elevated privileges. This can lead to unauthorized access, privilege escalation, and potentially remote code execution if combined with other vulnerabilities or misconfigurations. The unknown severity indicates that a CVSS score has not yet been formally published, but the potential impact is high due to the nature of session bypass and privilege escalation.
1. IMMEDIATE ACTIONS
a. Incident Response Activation: Immediately engage your organization's incident response team and follow established protocols for critical security incidents.
b. System Isolation: Identify and logically isolate any systems running the affected AcmeCorp Enterprise Application Server that are exposed to untrusted networks. This may involve firewall rules, network segmentation, or temporary shutdown if isolation is not feasible.
c. Log Review: Scrutinize all available application, web server, and authentication logs for the past several weeks for indicators of compromise. Look for unusual session IDs, rapid session creation from single IP addresses, unexpected privilege changes, multiple failed login attempts followed by a successful one from a different geographic location, or any errors related to session handling.
d. Force Session Invalidation: As a precautionary measure, force a global invalidation of all active user sessions across all instances of the affected application server. This will require all users to re-authenticate.
e. Credential Reset: For critical administrative accounts and accounts suspected of compromise, initiate an immediate password reset. Enforce strong, unique passwords.
f. Backup Critical Data: Perform immediate backups of all critical data and system configurations associated with the affected application server instances.
2. PATCH AND UPDATE INFORMATION
a. Vendor Advisories: Continuously monitor official AcmeCorp security advisories and support channels for the release of a security patch or updated versions of the AcmeCorp Enterprise Application Server that address CVE-2026-52778. Subscribe to their security notification services.
b. Patch Application: Once a vendor-provided patch is available, prioritize its deployment. Follow the vendor's instructions meticulously.
i. Test Environment: Apply the patch first in a non-production, representative test environment to verify functionality and stability before deploying to production.
ii. Backup: Prior to applying the patch in production, ensure complete system backups are performed.
iii. Staged Rollout: Consider a staged rollout for large environments to minimize potential service disruption.
c. Version Upgrade: If a patch is not available for your specific version, prepare for an upgrade to a patched or newer, secure version of the AcmeCorp Enterprise Application Server. Ensure compatibility testing is completed.
3. MITIGATION STRATEGIES
a. Multi-Factor Authentication (MFA): Enforce MFA for all user accounts, especially for administrative and privileged users. MFA significantly reduces the impact of session hijacking as a compromised session token alone may not grant full access.
b. Session Timeout Configuration: Implement aggressive session timeouts for all users, particularly for privileged accounts. Ensure inactive sessions are terminated promptly.
c. Session Fixation Prevention: Verify that the application server is configured to regenerate session IDs after successful authentication and that session IDs are not accepted from URL parameters. Implement IP-based session binding if supported and feasible.
d. Web Application Firewall (WAF) Rules: Deploy or update WAF rules to detect and block suspicious requests targeting session management endpoints. This may include rules for unusual cookie values, unexpected request sequences related to session creation, or attempts to reuse invalid session tokens.
e. Network Access Restrictions: Restrict network access to the AcmeCorp Enterprise Application Server to only necessary internal IP ranges and services. Implement strict ingress and egress filtering.
f. Rate Limiting: Implement rate limiting on authentication and session creation endpoints to hinder brute-force and session enumeration attacks.
g. Temporary Feature Disablement: If feasible and business-acceptable, temporarily disable specific features or modules that heavily rely on the vulnerable session management component until a patch can be applied.
4. DETECTION METHODS
a. SIEM and Log Analysis:
i. Correlate Events: Configure your Security Information and Event Management (SIEM) system to correlate authentication failures, session invalidations, privilege changes, and application errors related to session handling.