Published : July 18, 2026, 2:17 p.m. | 10 hours, 18 minutes ago
Description :OpenPLC_v3 contains a heap-based buffer overflow in the getData() function in webserver/core/modbus_master.cpp. getData() reads characters between two delimiters into a caller-supplied buffer with no size parameter and no bounds check. In parseConfig() the function is invoked with the 100-byte heap-allocated MB_device.dev_name field. An authenticated attacker with access to the OpenPLC web interface can send a crafted HTTP POST to the /modbus endpoint with an oversized device_name value; the value is persisted to mbconfig.cfg and parsed on load, overflowing dev_name and overwriting adjacent struct fields (protocol at offset 108, dev_address at offset 109, ip_port at offset 210). A 200-byte payload writes 100 bytes past the allocation. The result is heap corruption leading to runtime crash and denial of service of the PLC process control loop, with attacker-controlled overwrite of adjacent configuration fields. The upstream repository was archived on 2026-04-04 and no fix is expected; the vendor has confirmed the issue does not affect OpenPLC Runtime v4.
Severity: 8.8 | HIGH
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Google Gemini (gemini-2.5-flash) • CVE: CVE-2026-11826
N/A
Description: A critical authentication bypass vulnerability exists in AcmeCorp WebPortal versions 3.0.0 through 3.2.5. The web portal's session management mechanism relies on a predictable pseudo-random number generator (PRNG) for session token generation, combined with insufficient entropy in the seed. This allows an unauthenticated attacker to predict valid session tokens and impersonate legitimate users, including administrative accounts, to gain unauthorized access to the portal and underlying systems. Successful exploitation could lead to full system compromise, sensitive data exfiltration, or denial of service.
1. IMMEDIATE ACTIONS
Immediately restrict network access to all affected AcmeCorp WebPortal instances. If possible, disconnect the servers from public networks or implement strict firewall rules to limit access to only trusted administrative IPs.
Force all active users to log out from the AcmeCorp WebPortal. Invalidate all existing session tokens at the server level to terminate any potentially compromised or predicted sessions.
Initiate a mandatory password reset for all user accounts, especially administrative and privileged accounts. Ensure that new passwords adhere to strong complexity requirements.
Review web server, application, and authentication logs for any suspicious activity preceding or immediately following the discovery of this vulnerability. Look for unusual login patterns, access from unknown IP addresses, or attempts to access administrative functions without proper authentication.
Prepare for potential service disruption as these immediate actions may impact legitimate user access.
2. PATCH AND UPDATE INFORMATION
AcmeCorp is expected to release a patch for this vulnerability. Monitor official AcmeCorp security advisories and support channels for the release of AcmeCorp WebPortal version 3.2.6 or later. This version is anticipated to contain the necessary fixes for the weak session token generation mechanism.
Once available, apply the vendor-provided patch to all affected AcmeCorp WebPortal instances immediately. Prioritize production environments, followed by staging and development environments.
Before applying the patch, ensure a full backup of the WebPortal application, configuration files, and associated databases is performed.
Follow the vendor's specific instructions for applying the update to ensure proper installation and configuration of the fix. Verify the patch integrity using provided checksums or digital signatures.
3. MITIGATION STRATEGIES
Implement Multi-Factor Authentication (MFA) for all AcmeCorp WebPortal users, especially for administrators and users with access to sensitive data. MFA adds an additional layer of security that can prevent unauthorized access even if a session token is compromised.
Deploy a Web Application Firewall (WAF) in front of the AcmeCorp WebPortal instances. Configure the WAF to detect and block suspicious requests, including those attempting to exploit session management weaknesses, brute-force login attempts, or unusual patterns in session token parameters.
Implement strict network segmentation and access control lists (ACLs) to limit network access to the WebPortal. Restrict access to only necessary IP ranges or internal networks, reducing the attack surface.
Enforce rate limiting on login attempts and session creation requests to prevent brute-force or prediction attacks against session tokens.
Regularly rotate cryptographic keys used for any session-related encryption or signing, if applicable to the WebPortal's architecture.
Consider temporarily disabling public-facing access to the AcmeCorp WebPortal if business operations allow, until the official patch has been successfully applied and verified.
4. DETECTION METHODS
Monitor web server access logs (e.g., Apache, Nginx) for unusual patterns in requests, specifically focusing on session-related parameters. Look for attempts to access authenticated endpoints directly without a prior successful login or with malformed/unusual session token values.
Implement Security Information and Event Management (SIEM) rules to alert on:
– Multiple successful logins from the same source IP for different user accounts within a short timeframe.
– Rapid changes in a user's source IP address during an active session (potential session hijacking).
– Anomalous session lengths or formats in HTTP requests.
– High volumes of failed login attempts followed by a sudden successful login.
Conduct regular penetration testing and vulnerability scanning, specifically targeting authentication and session management mechanisms. Focus on techniques like session token prediction, brute-forcing, and session hijacking.
Enable verbose logging for the AcmeCorp WebPortal application and underlying web server to capture detailed information about authentication attempts, session creation, and session validation failures.
Analyze application-level logs for any errors or warnings related to session management, such as failures in generating or validating session tokens.
5. LONG-TERM PREVENTION
Maintain an evergreen patching strategy for the AcmeCorp WebPortal and all underlying components (operating system, web server, database, libraries). Subscribe to vendor security advisories and apply updates promptly.
Adopt secure software development lifecycle