CVE-2026-9507

What it is

A session fixation vulnerability has been identified in osTicket v1.18.2. This security flaw allows an attacker to hijack a victim’s account by keeping the initial session identifier (OSTSESSID) active after a successful login. The issue lies in the fact that the application does not invalidate the pre-authentication cookie or generate a new identifier for the authenticated context. As a result, if an attacker manages to set a known session identifier in the victim’s browser, they will be able to maintain unauthorised access to the account once the victim has authenticated.

At a glance

Exploitability

Can be exploited over the network without logging in, but needs a user to act. Limited direct impact.

Exploit odds

0.4% chance of exploitation in the next 30 days (EPSS).

Fix

No patch or advisory is linked yet. Look at mitigations or restrict exposure.

Timeline

1. 2026-06-16 13:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-26 12:10 UTC Last updatedMost recent change to the record

Details

Published

2026-06-16 13:16 UTC

Last modified

2026-10-26 12:10 UTC

Exploit probability

0.4% · EPSS, next 30 days

Weakness

CWE-38

Record status

Deferred

Attack profile CVSS 4.0 · 5.1

Attack vector

Network

Complexity

Low

Attack requirements

None

Privileges needed

None

User interaction

Active

Confidentiality

Low

Integrity

Low

Availability

None