PatchSiren cyber security CVE debrief

CVE-2026-1816 Turkiye Electricity Transmission Corporation (TEİAŞ) CVE debrief

CVE-2026-1816 describes an improper restriction of excessive authentication attempts in the TEİAŞ Mobile Application. In the affected release range, 1.6.2 through versions before 1.13, the application may allow brute-force attempts against authentication. The published CVSS vector indicates network reachability, low attack complexity, low privileges, and required user interaction, with the main impact on confidentiality.

Vendor: Turkiye Electricity Transmission Corporation (TEİAŞ)
Product: Mobile Application
CVSS: MEDIUM 6.3
CISA KEV: Not listed in stored evidence
Original CVE published: 2026-05-21
Original CVE updated: 2026-05-21
Advisory published: 2026-05-21
Advisory updated: 2026-05-21

Who should care

Organizations and users running TEİAŞ Mobile Application versions from 1.6.2 up to, but not including, 1.13 should care most. Security teams responsible for account protection, authentication controls, and mobile-app backend monitoring should also review exposure and update plans.

Technical summary

The issue is classified as CWE-307 (Improper Restriction of Excessive Authentication Attempts). According to the supplied NVD metadata, the CVSS v3.1 vector is AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:L/A:N, which is consistent with a remotely reachable authentication weakness where an attacker with limited privileges and user interaction may be able to repeatedly attempt logins. The supplied source reference is a USOM/TEİAŞ security notice link, and NVD lists the vulnerability status as Deferred.

Defensive priority

Medium. Prioritize remediation if the mobile app is in active use, protects sensitive accounts, or sits behind other identity systems that could be abused for account takeover. The combination of brute-force exposure and high confidentiality impact makes timely mitigation important, even though user interaction is required.

Recommended defensive actions

Upgrade the TEİAŞ Mobile Application to version 1.13 or later.
Confirm whether authentication throttling, lockout, step-up verification, or CAPTCHA-style controls are enforced server-side as well as in the client.
Review logs for repeated failed authentication attempts and unusual login patterns.
Enable or strengthen MFA where available to reduce the value of brute-force attempts.
Validate that rate limiting and account protection controls apply consistently across all authentication endpoints used by the app.

Evidence notes

This debrief is based only on the supplied official-source corpus: the NVD CVE record metadata, the CVE.org record link, and the referenced USOM/TEİAŞ security notice URL. The CVE was published and last modified on 2026-05-21 in the provided data. NVD metadata marks the vulnerability status as Deferred. The vendor attribution in the supplied corpus is weak/uncertain, so the debrief keeps the product reference aligned to the description rather than asserting additional vendor details.

Official resources

CVE-2026-1816 was published on 2026-05-21 and modified later the same day in the supplied records. The supplied NVD metadata points to a TEİAŞ mobile-application security notice and identifies the issue as a brute-force/authentication-attem