CVE-2026-15586 in Ontime
Summary
by MITRE • 10/27/2026
Improper restriction of excessive authentication attempts vulnerability in İdvlabs Software and Consulting Services Inc. Ontime allows Brute Force.
This issue affects Ontime: through 2026-10-27. NOTE: The vendor was contacted early about this disclosure but did not respond in any way.
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Analysis
by VulDB Data Team • 10/27/2026
The vulnerability identified as an improper restriction of excessive authentication attempts within the OnTime software, developed by İdvlabs Software and Consulting Services Inc., represents a critical security flaw that undermines the integrity of user access controls. This specific weakness allows attackers to perform brute force attacks against the application's login mechanisms without encountering effective rate limiting or account lockout policies. By failing to restrict the number of authentication attempts within a given timeframe, the system exposes itself to automated credential stuffing and password guessing techniques, which are among the most prevalent methods used by threat actors to gain unauthorized access to enterprise systems. The vulnerability affects versions of OnTime up through October 27, 2026, indicating that this is a persistent issue in current deployments unless patched or mitigated externally.
From a technical perspective, the absence of robust authentication throttling mechanisms means that an attacker can submit thousands of login requests per minute using automated scripts. This lack of control allows for rapid iteration through common passwords or leaked credential databases without triggering defensive alerts such as CAPTCHAs, temporary account locks, or IP-based bans. In enterprise environments where OnTime is often used for project management and resource scheduling, the compromise of even a single user account can serve as an initial foothold for lateral movement within the network. The severity of this flaw is compounded by the fact that it directly violates fundamental principles of secure authentication design, which mandate that systems must actively resist automated guessing attacks to protect sensitive data and operational continuity.
The operational impact of this vulnerability extends beyond simple unauthorized access. If attackers successfully compromise user credentials through brute force, they may exploit elevated privileges associated with administrative or managerial roles within the OnTime platform. This could lead to the manipulation of project timelines, theft of proprietary intellectual property stored in task descriptions or attachments, and disruption of business operations by altering resource allocations or deleting critical data. Furthermore, because OnTime is often integrated with other enterprise tools such as email servers, calendars, and collaboration platforms, a compromised account can facilitate phishing campaigns against colleagues or provide access to broader network segments if single sign-on mechanisms are in place. The lack of response from the vendor further exacerbates the risk, leaving organizations without official patches or guidance for remediation during this extended window until at least late 2026.
This vulnerability aligns with CWE-307, which describes Improper Restriction of Excessive Authentication Attempts, and is closely related to MITRE ATT&CK technique T1110, known as Brute Force. Organizations relying on OnTime must recognize that this flaw places them at significant risk during the attack phase where adversaries attempt to gain initial access through credential-based attacks. The failure to implement basic rate limiting or multi-factor authentication enforcement leaves a wide-open vector for exploitation by both opportunistic script kiddies and sophisticated threat actors seeking persistent access.
To mitigate these risks in the absence of vendor-provided patches, organizations should implement compensating controls at the network perimeter and application layer. Deploying Web Application Firewalls with specific rules to detect and block rapid successive login failures from single IP addresses can effectively simulate rate limiting. Additionally, enforcing multi-factor authentication for all user accounts adds a critical second layer of defense that renders stolen or guessed passwords insufficient for access. Network segmentation should also be reviewed to ensure that the OnTime server is not directly exposed to untrusted networks without additional protective measures. Regular monitoring of authentication logs for anomalous patterns, such as spikes in failed login attempts from specific geographic locations or user agents, can help detect ongoing brute force campaigns early enough to block them before successful compromise occurs.