CVE-2026-1989: PAVO Pay Auth Bypass Vulnerability

CVE-2026-1989 Overview

CVE-2026-1989 is an authorization bypass vulnerability in PAVO Pay from PAVO Financial Technology Solutions Inc. The flaw stems from improper validation of user-controlled identifiers, allowing attackers to exploit trusted identifiers to access resources belonging to other users. This weakness is classified as [CWE-639] Authorization Bypass Through User-Controlled Key, commonly known as Insecure Direct Object Reference (IDOR). The vulnerability affects PAVO Pay through version 09072026. According to the disclosure, the vendor was contacted early but did not respond. The issue can be exploited over the network without authentication or user interaction, exposing sensitive financial data.

Critical Impact
Unauthenticated remote attackers can manipulate trusted identifiers to access data belonging to other PAVO Pay users, resulting in high confidentiality impact on a financial technology platform.

Affected Products

PAVO Pay through 09072026
PAVO Financial Technology Solutions Inc. mobile and web clients relying on the affected API
Any integrations invoking PAVO Pay endpoints that accept user-controlled resource identifiers

Discovery Timeline

2026-07-09 - CVE-2026-1989 published to NVD
2026-07-09 - Last updated in NVD database
Vendor status - PAVO Financial Technology Solutions Inc. was contacted early about the disclosure but did not respond

Technical Details for CVE-2026-1989

Vulnerability Analysis

The vulnerability resides in PAVO Pay's authorization logic. The application accepts identifiers supplied by the client, such as account numbers, transaction IDs, or user references, and uses them to retrieve resources without verifying that the requesting session owns the object. This pattern matches [CWE-639], where the server trusts a client-supplied key as an implicit authorization token. An attacker who enumerates or guesses valid identifiers can retrieve data associated with other accounts. The attack is fully remote and requires no privileges or user interaction, per the published attack vector.

Root Cause

The root cause is missing object-level authorization on requests that reference user data by identifier. PAVO Pay treats the presence of a valid session as sufficient to serve any record matching the supplied key. It does not enforce a check that binds the authenticated principal to the requested resource. Trusted identifiers such as customer IDs or payment references are exposed to the client and later re-submitted, giving an attacker direct control over which record the backend fetches.

Attack Vector

An attacker authenticates or interacts with the PAVO Pay API as a normal client. The attacker then replaces the identifier in a request, for example a numeric user ID or transaction reference, with a value belonging to a different account. Because the server does not validate ownership, it returns the target resource. Sequential or predictable identifiers make bulk enumeration practical. The vulnerability is exploitable over the network without credentials, which increases the potential scope of data exposure across the platform.

No verified proof-of-concept code is available. For technical context, refer to the Siber Güvenlik Notification TR-26-0521.

Detection Methods for CVE-2026-1989

Indicators of Compromise

Sequential or non-sequential enumeration of numeric identifiers in PAVO Pay API requests from a single client or IP
HTTP 200 responses returning resources whose owner does not match the authenticated session identifier
Elevated volume of GET or POST requests to endpoints containing user, account, or transaction IDs
Anomalous access patterns where a single session accesses many distinct user records in a short window

Detection Strategies

Enable verbose application logging that records the authenticated principal alongside the resource identifier accessed on every request
Correlate session ownership with requested object ownership in a SIEM to flag mismatches
Baseline normal per-user object access rates and alert on statistical outliers indicative of enumeration
Deploy web application firewall rules that identify identifier tampering and rapid sequential ID access

Monitoring Recommendations

Monitor API gateway logs for high-cardinality identifier access from single tokens or IP addresses
Track failed and successful authorization checks separately to surface bypass attempts
Alert on any endpoint returning records where the response payload's owner field differs from the caller's identity
Retain access logs long enough to support retrospective hunts once a vendor patch is issued

How to Mitigate CVE-2026-1989

Immediate Actions Required

Restrict exposure of PAVO Pay endpoints that accept user-controlled identifiers, using network controls or API gateway policies
Implement compensating server-side authorization checks in any intermediary proxy that binds session identity to resource ownership
Rotate or invalidate any long-lived tokens that may have been used for enumeration
Notify PAVO Financial Technology Solutions Inc. and request status on a fix given the lack of vendor response

Patch Information

No vendor patch has been published at the time of disclosure. The vendor did not respond to the researcher's contact attempts. Affected organizations should track updates from PAVO Financial Technology Solutions Inc. and the Turkish national cybersecurity authority for future advisories.

Workarounds

Place an authenticating reverse proxy in front of PAVO Pay APIs that re-validates ownership of the requested identifier against the session
Replace exposed sequential identifiers with unpredictable opaque tokens (UUIDv4 or signed references) at the proxy layer
Apply rate limiting to endpoints that accept identifiers to slow enumeration until a patch is available
Restrict API access to known client IP ranges or require mutual TLS for high-risk endpoints

bash

# Example NGINX configuration to rate limit identifier-based endpoints
limit_req_zone $binary_remote_addr zone=pavo_api:10m rate=10r/m;

server {
    location /api/v1/ {
        limit_req zone=pavo_api burst=5 nodelay;
        proxy_pass https://pavo-pay-backend.internal;
        proxy_set_header X-Forwarded-User $remote_user;
    }
}