CVE-2026-31903

High

Published: 20 March 2026

Published

20 March 2026

Modified

06 May 2026

KEV Added

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Patch

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CVSS Score 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Score 0.0003 8.6th percentile

Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-31903 is a high-severity Improper Restriction of Excessive Authentication Attempts (CWE-307) vulnerability in Igl Eparking.Fi. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Password Guessing (T1110.001); ranked at the 8.6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified are NIST 800-53 AC-7 (Unsuccessful Logon Attempts) and SC-5 (Denial-of-service Protection).

Threat & Defense at a Glance

What attackers do: exploitation maps to Password Guessing (T1110.001) and 1 other technique. What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

AC-7 Unsuccessful Logon Attempts good match

prevent

Directly addresses the absence of rate limiting on authentication requests by enforcing limits on consecutive unsuccessful logon attempts, preventing both brute-force attacks and DoS via excessive auth floods.

SC-5 Denial-of-service Protection good match

prevent

Provides comprehensive denial-of-service protection tailored to resource exhaustion from unlimited authentication requests overwhelming the WebSocket API and suppressing charger telemetry.

SI-9 Information Input Restrictions partial match

prevent

Enforces information input restrictions at system interfaces, enabling limits on the volume or rate of WebSocket authentication requests to mitigate flooding.

MITRE ATT&CK Enterprise TechniquesAI

T1110.001 Password Guessing Credential Access

Adversaries with no prior knowledge of legitimate credentials within the system or environment may guess passwords to attempt access to accounts.

attack.mitre.org →

T1499.003 Application Exhaustion Flood Impact

Adversaries may target resource intensive features of applications to cause a denial of service (DoS), denying availability to those applications.

attack.mitre.org →

Why these techniques?

Lack of rate limiting on WebSocket auth requests directly enables password guessing (T1110.001) via excessive attempts and application-layer request flooding leading to service exhaustion/DoS on telemetry components (T1499.003).

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

NVD Description

The WebSocket Application Programming Interface lacks restrictions on the number of authentication requests. This absence of rate limiting may allow an attacker to conduct denial-of-service attacks by suppressing or mis-routing legitimate charger telemetry, or conduct brute-force attacks to gain unauthorized…

access.

Deeper analysisAI

CVE-2026-31903 is a vulnerability in the WebSocket Application Programming Interface that lacks restrictions on the number of authentication requests due to the absence of rate limiting. This issue, associated with CWE-307 (Improper Restriction of Excessive Authentication Attempts), affects components handling charger telemetry and carries a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H). It was published on 2026-03-20.

Remote attackers require no privileges or user interaction to exploit this vulnerability over the network with low complexity. Successful exploitation enables denial-of-service attacks by suppressing or mis-routing legitimate charger telemetry traffic, or brute-force attacks to achieve unauthorized access, primarily impacting availability.

Mitigation details are provided in CISA's ICS advisory ICSA-26-078-08, available at https://www.cisa.gov/news-events/ics-advisories/icsa-26-078-08 and the corresponding CSAF JSON file at https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-078-08.json.