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Vulnerability record · CVE-2026-15389 · published 14 July 2026

CVE-2026-15389: Insecure direct object reference vulnerability

A vulnerability relating to insufficient access control has been identified in the session management of the Sesame Time web application and its REST v3 API. The flaw lies in the fact that the system uses the session identifier (USID) as the sole validation mechanism, without verifying whether that identifier legitimately belongs to the user making the request. As a result, an attacker who obtains a valid USID can impersonate a victim’s session and access their confidential information, including emails, user IDs, roles and corporate data. This vulnerability is exacerbated by poor session lifecycle management: new logins generate additional USIDs without revoking the previous ones, allowing multiple active sessions to coexist and thereby expanding the attack surface.

8.7 CVSS 4.0 High EPSS 0.44% · top 64.2% CWE-639 · Insecure direct object reference Deferred
8.7CVSS 4.0 base score
0.44%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
1References
15 Jul 2026Last modified by NVD

Description

A vulnerability relating to insufficient access control has been identified in the session management of the Sesame Time web application and its REST v3 API. The flaw lies in the fact that the system uses the session identifier (USID) as the sole validation mechanism, without verifying whether that identifier legitimately belongs to the user making the request. As a result, an attacker who obtains a valid USID can impersonate a victim’s session and access their confidential information, including emails, user IDs, roles and corporate data. This vulnerability is exacerbated by poor session lifecycle management: new logins generate additional USIDs without revoking the previous ones, allowing multiple active sessions to coexist and thereby expanding the attack surface.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

References

LinkTags
https://www.incibe.es/en/incibe-cert/notices/aviso/inadequate-access-control-sesame-time-session-management

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

8.4CVE-2026-55255Langflow IDOR in responses endpoint allows cross-user flow executionLangflow before 1.9.1 has an insecure direct object reference in the /api/v1/responses endpoint. An authenticated attacker can supply another user's …KEVEPSS 0.89%analysed

Source: NIST National Vulnerability Database (record CVE-2026-15389), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.