Low
Discourse doesn't validate destination topic when moving posts
Type: advisorySources: OSV
Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, the `move_posts` action only checked `can_move_posts?` on the source topic but never validated write permissions on the destination topic. This allowed TL4 users and category group moderators to move posts into topics in categories where they lack posting privileges (e.g., read-only categories or categories with group-restricted write access). Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. No known workarounds are available.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-27151
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 4 Nov 2026, 18:05 UTC · Revision 1
Source evidence
Discourse doesn't validate destination topic when moving posts
core-osv · Original sourcePublished 26 Feb 2026, 19:57 UTC
Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, the `move_posts` action only checked `can_move_posts?` on the source topic but never validated write permissions on the destination topic. This allowed TL4 users and category group moderators to move posts into topics in categories where they lack posting privileges (e.g., read-only categories or categories with group-restricted write access). Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. No known workarounds are available.
osv:CVE-2026-27151
Complete source record
{
"id": "65a7d877deed601fd2babd27ab4d0a4694e1d1f70231989b13ba7ea474f2c6d4",
"url": "https://osv.dev/vulnerability/CVE-2026-27151",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "Discourse doesn't validate destination topic when moving posts",
"summary": "Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, the `move_posts` action only checked `can_move_posts?` on the source topic but never validated write permissions on the destination topic. This allowed TL4 users and category group moderators to move posts into topics in categories where they lack posting privileges (e.g., read-only categories or categories with group-restricted write access). Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. No known workarounds are available.",
"evidence": "osv:CVE-2026-27151",
"products": [],
"severity": "low",
"structured": {
"id": "CVE-2026-27151",
"aliases": [
"BIT-discourse-2026-27151",
"CVE-2026-27151",
"GHSA-m69h-9m2g-cfgw"
],
"metrics": [
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U"
}
],
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"modified": "2026-10-28T02:30:38.474698238Z",
"provider": "osv",
"references": [
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"https://github.com/discourse/discourse/security/advisories/GHSA-m69h-9m2g-cfgw",
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"source_id": "core-osv",
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"published_at": "2026-02-26T19:57:06.92+00:00"
}