CVE-2026-9507

CVE-2026-9507 is a medium-severity vulnerability with a CVSS 4.0 base score of 5.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-38.

Key facts

Description

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.

Frequently asked questions

What is CVE-2026-9507?
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.
How severe is CVE-2026-9507?
CVE-2026-9507 has a CVSS 4.0 base score of 5.1, rated medium severity.
Is CVE-2026-9507 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (32nd percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-9507?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-9507 have an EU (EUVD) identifier?
Yes. CVE-2026-9507 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-37079.
When was CVE-2026-9507 published?
CVE-2026-9507 was published on 2026-06-16 and last updated on 2026-06-17.

References