Vendor
2 published CVES affecting ltsp, from public sources (CVE.org, NVD, CISA KEV, FIRST EPSS, OSV).
Newest publication first
LTSP LDM through 2.18.06 allows fat-client root access because the LDM_USERNAME variable may have an empty value if the user's shell lacks support for Bourne shell syntax. This is related to a run-x-session script.
ldm in Linux Terminal Server Project (LTSP) 0.99 and 2 passes the -ac option to the X server on each LTSP client, which allows remote attackers to connect to this server via TCP port 6006 (aka display :6).
Sources: CVE.org, NVD, CISA KEV, FIRST EPSS, OSV and public exploit-reference metadata. Product matching comes from the published CVE records. A proof-of-concept means public code exists; it is not evidence of exploitation.