CVE-2026-15389
Session ID-only auth allows attacker to impersonate users and access sensitive data.
Is CVE-2026-15389 being exploited?
Not confirmed. CVE-2026-15389 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.44% probability of exploitation in the next 30 days.
How severe is CVE-2026-15389?
CVE-2026-15389 is rated High with a CVSS score of 8.7. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-15389?
Not known from our data. No patch reference has been recorded for CVE-2026-15389, which is not the same as no patch existing — a fix may have shipped without a tagged reference, or after this record was written. The vendor advisory is the only authority on whether a fix exists, and mitigations may be available regardless.
What does CVE-2026-15389 affect?
CVE-2026-15389 affects Sesame Time web application, Sesame Time REST v3 API, Sesame Time session management. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-15389?
Validate session ownership; revoke/rotate USIDs at login; use signed, bound tokens and short expiries.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Stolen USID enables session hijack: attacker can impersonate users and access emails, user IDs, roles and corporate data; old USIDs remain valid.
Immediate action required
- affected< *
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.