Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, plugins/chat/lib/chat/onebox_handler.rb resolves Chat::Thread by route thread_id independently of the route channel_id before checking whether the user can preview the selected chat channel. An authenticated user can pair a public channel ID with a private thread ID in a /onebox.json request and obtain private thread message content. This issue is fixed in versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0.
{
"cna_assigner": "GitHub_M",
"cwe_ids": [
"CWE-639"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72724.json"
}{
"extracted_events": [
{
"introduced": "0"
},
{
"fixed": "2026.1.6"
},
{
"introduced": "2026.5.0-latest"
},
{
"fixed": "2026.5.2"
},
{
"introduced": "2026.6.0-latest"
},
{
"fixed": "2026.6.1"
},
{
"introduced": "2026.7.0-latest"
},
{
"fixed": "2026.7.0"
}
],
"source": [
"AFFECTED_FIELD",
"REFERENCES"
]
}