CVE-2021-43793: Bypass of Poll voting limits in Discourse

Severity: medium (CVSS 4.0 v2.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.8% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-12-01 · updated 2026-06-17
Weakness: CWE-269

Description

Discourse is an open source discussion platform. In affected versions a vulnerability in the Polls feature allowed users to vote multiple times in a single-option poll. The problem is patched in the latest tests-passed, beta and stable versions of Discourse

Affected products

discourse: before 2.7.11; 2.8.0-beta1, 2.8.0-beta2, 2.8.0-beta3, 2.8.0-beta4, 2.8.0-beta5, 2.8.0-beta6 (+1) — fixed in 2.7.11

How to fix

Upgrade to a fixed version: discourse 2.7.11. Check the vendor advisory for mitigations.

References

https://github.com/discourse/discourse/commit/0c6b9df77bac9c6f7c7e2eadf6fe100064afdeab
https://github.com/discourse/discourse/commit/1d0faedfbc3a8b77b971dc70d25e30791dbb6e0b
https://github.com/discourse/discourse/security/advisories/GHSA-jq7h-44vc-h6qx
https://github.com/discourse/discourse/commit/0c6b9df77bac9c6f7c7e2eadf6fe100064afdeab
https://github.com/discourse/discourse/commit/1d0faedfbc3a8b77b971dc70d25e30791dbb6e0b
https://github.com/discourse/discourse/security/advisories/GHSA-jq7h-44vc-h6qx

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