What’s Vulnerable › Vulnerabilities

CVE-2026-72723: Discourse: Anonymous sidebar serialization exposes descriptions of category-restricted tags

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-10 · updated 2026-09-08
• Weakness: CWE-862

Description

Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, SiteSerializer.anonymous_default_navigation_menu_tags serializes tags from SiteSetting.default_navigation_menu_tags without applying DiscourseTagging.filter_visible for the anonymous viewer. An unauthenticated user can retrieve restricted tag names and descriptions through /site.json when those tags are limited by inaccessible categories, category tag groups, or tag-group permissions. This issue is fixed in versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0.

Affected products

• discourse: before 2026.1.6; from 2026.5.0-latest, < 2026.5.2; from 2026.6.0-latest, < 2026.6.1; from 2026.7.0-latest, < 2026.7.0

References

• https://github.com/discourse/discourse/commit/0248e9ca82d0493037a9ca04d73904ccfad795f9
• https://github.com/discourse/discourse/commit/03444ddb74d535dda557350f4c5800a6ec2669d7
• https://github.com/discourse/discourse/commit/900f51c147913f667e64484c2f2dd48c723314ac
• https://github.com/discourse/discourse/commit/da84c677213cac3b024e753f180f45472b89efde
• https://github.com/discourse/discourse/pull/42091
• https://github.com/discourse/discourse/pull/42092
• https://github.com/discourse/discourse/pull/42093
• https://github.com/discourse/discourse/pull/42094
• https://github.com/discourse/discourse/security/advisories/GHSA-4p6q-h74v-5j7p

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