CVE-2026-31805 PUBLISHED

Discourse has a poll authorization bypass via post_id array parameter

Assigner: GitHub_M
Reserved: 09.03.2026 Published: 20.03.2026 Updated: 20.03.2026

Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, an authorization bypass in the poll plugin allowed authenticated users to vote on, remove votes from, or toggle the open/closed status of polls they did not have access to. By passing post_id as an array (e.g. post_id[]=&post_id[]=), the authorization check resolves to the accessible post while the poll lookup resolves to a different post's poll. This affects the vote, remove_vote, and toggle_status endpoints in DiscoursePoll::PollsController. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
CVSS Score: 5.3

Product Status

Vendor discourse
Product discourse
Versions
  • Version >= 2026.1.0-latest, < 2026.1.2 is affected
  • Version >= 2026.2.0-latest, < 2026.2.1 is affected
  • Version = 2026.3.0-latest.1 is affected

References

Problem Types

  • CWE-863: Incorrect Authorization CWE
  • CWE-20: Improper Input Validation CWE