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PatchSiren cyber security CVE debrief

CVE-2023-4934 Usta CVE debrief

CVE-2023-4934 is a high-severity authorization bypass issue in Usta AYBS affecting versions before 1.0.3. The vulnerability is described as a user-controlled key problem that can lead to authentication abuse and authentication bypass. Based on the published CVSS v3.1 vector, the issue is network-reachable, low-complexity, and has high impact to confidentiality, integrity, and availability. Organizations running affected AYBS versions should prioritize remediation, especially if the application is exposed to untrusted networks or supports sensitive accounts and workflows.

Vendor
Usta
Product
AYBS
CVSS
HIGH 8.8
CISA KEV
Not listed in stored evidence
Original CVE published
2023-09-27
Original CVE updated
2026-05-21
Advisory published
2023-09-27
Advisory updated
2026-05-21

Who should care

Administrators, operators, and developers responsible for Usta AYBS deployments should care, especially anyone running versions earlier than 1.0.3. Security teams should also review any integrations or access paths that rely on AYBS authorization decisions.

Technical summary

NVD describes the issue as an authorization bypass through a user-controlled key in Usta AYBS, affecting versions before 1.0.3. The advisory mapping includes CWE-639 and a CVSS 3.1 vector of AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H, indicating a remotely reachable flaw with low attack complexity and significant potential impact once an attacker has the required low privileges. The public record references USOM/Siber Güvenlik advisory material for additional context.

Defensive priority

High. The combination of remote reachability, low complexity, and high impact makes this a priority fix for affected deployments before 1.0.3.

Recommended defensive actions

  • Upgrade Usta AYBS to version 1.0.3 or later.
  • Confirm whether any deployed instances are running affected versions before 1.0.3.
  • Review authorization logic that uses user-supplied keys and verify that keys cannot be manipulated to bypass access checks.
  • Restrict access to AYBS to trusted networks where feasible until patched.
  • Audit logs and access activity for unexpected authentication or authorization behavior around affected systems.

Evidence notes

All claims are limited to the supplied NVD record and linked USOM/Siber Güvenlik references. The CVE was published on 2023-09-27 and is marked modified on 2026-05-21 in the provided record. No KEV listing, ransomware association, or exploit details were provided in the source corpus.

Official resources

Publicly disclosed in the official CVE/NVD record on 2023-09-27; the supplied NVD record was last modified on 2026-05-21.