CVE-2026-7484: AVESİS Privilege Escalation Vulnerability

CVE-2026-7484 Overview

CVE-2026-7484 is an access control weakness in ABIS Technology Ltd. Co. AVESİS. The vulnerability allows external control of an assumed-immutable web parameter [CWE-472], enabling attackers to reach functionality that is not properly constrained by access control lists (ACLs). Remote attackers can manipulate client-controlled parameters over the network without authentication or user interaction. The issue affects AVESİS versions prior to 202606251646. Successful exploitation exposes restricted functionality and confidential information to unauthorized users.

Critical Impact
Unauthenticated remote attackers can tamper with web parameters treated as immutable by AVESİS to access functionality guarded only by client-side controls, resulting in unauthorized disclosure of confidential data.

Affected Products

ABIS Technology Ltd. Co. AVESİS versions before 202606251646

Discovery Timeline

2026-07-24 - CVE-2026-7484 published to NVD
2026-07-24 - Last updated in NVD database

Technical Details for CVE-2026-7484

Vulnerability Analysis

AVESİS relies on web parameters that the application assumes cannot be modified by end users. Attackers can alter these parameters in HTTP requests to reach application functionality that should be restricted. The flaw is classified under CWE-472: External Control of Assumed-Immutable Web Parameter. Because access decisions depend on client-supplied values rather than server-side authorization, ACL enforcement is bypassed. The result is unauthorized read access to information that should be gated by proper access controls.

Root Cause

The root cause is trust in client-controlled input for authorization decisions. AVESİS treats hidden form fields, query string arguments, or cookie values as trusted and does not re-validate them against server-side session state. When users tamper with these values, the application grants access to functionality bound to a different privilege level or user context. This is a classic broken access control pattern where authentication may be present, but authorization is delegated to values under the attacker's control.

Attack Vector

The attack vector is remote and network-based, requires low attack complexity, no privileges, and no user interaction. An attacker sends crafted HTTP requests with modified parameter values to AVESİS endpoints. By adjusting identifiers, role indicators, or state fields in URLs, form bodies, or cookies, the attacker reaches functionality not permitted for their session. The vulnerability compromises confidentiality; integrity and availability are not directly affected. See the Siber Güvenlik Notification TR-26-0634 for the official advisory.

Detection Methods for CVE-2026-7484

Indicators of Compromise

Repeated HTTP requests to AVESİS endpoints with sequentially or unexpectedly modified numeric identifiers, role parameters, or object references.
Access log entries showing a single session retrieving resources tied to multiple distinct user identifiers or tenant scopes.
Anomalous parameter tampering patterns such as manipulated hidden form fields or unexpected values in query strings and cookies.

Detection Strategies

Deploy Web Application Firewall (WAF) rules that flag out-of-range or unexpected values in known-sensitive AVESİS parameters.
Correlate authentication events with subsequent object access to identify sessions retrieving resources outside the authenticated user's authorization scope.
Baseline normal parameter values per endpoint and alert on deviations that suggest forced browsing or IDOR-style probing.

Monitoring Recommendations

Enable verbose logging on AVESİS application servers, capturing full request URIs, parameter names, and session identifiers.
Forward AVESİS web server logs to a centralized SIEM for correlation with authentication and privilege-change events.
Review reverse proxy and load balancer logs for high-frequency parameter iteration originating from single source IP addresses or session tokens.

How to Mitigate CVE-2026-7484

Immediate Actions Required

Upgrade AVESİS to build 202606251646 or later immediately following vendor guidance in TR-26-0634.
Inventory all AVESİS instances exposed to untrusted networks and restrict access to trusted sources until patching is complete.
Audit application logs retroactively for evidence of parameter tampering and unauthorized functionality access.

Patch Information

ABIS Technology Ltd. Co. has addressed CVE-2026-7484 in AVESİS version 202606251646. Administrators should apply this update as the authoritative remediation. Refer to the Siber Güvenlik Notification TR-26-0634 issued by the Turkish national cybersecurity authority for details on the fix and vendor coordination.

Workarounds

Restrict access to AVESİS through network-level controls such as VPN or IP allow-listing until the patch is applied.
Deploy WAF rules that validate parameter formats and reject requests with tampered identifiers or role fields.
Enforce server-side authorization checks at every request boundary, treating all client-supplied parameters as untrusted.

bash

# Example WAF rule concept (ModSecurity syntax) to block suspicious parameter tampering
SecRule ARGS:userId "!@rx ^[0-9]+$" \
  "id:1007484,phase:2,deny,status:403,\
  msg:'CVE-2026-7484: Potential AVESIS parameter tampering'"