Communication and Collaboration

In Discourse versions prior to 3.5.4, 2025.11.2, 2025.12.1 and 2026.1.0 a medium severity vulnerability CVE-2026-24742 was detected. This vulnerability allows non-administrator moderators to access sensitive administrator-only data via staff action logs, including webhook secrets, API keys, private messages, and restricted settings, potentially enabling confidential data leakage and webhook spoofing. To address this issue, users should upgrade Discourse versions 3.5.4, 2025.11.2, 2025.12.1 or 2026.1.0. For more details, visit https://nvd.nist.gov/vuln/detail/CVE-2026-24742.

In Discourse versions prior to 3.5.4, 2025.11.2, 2025.12.1 and 2026.1.0 a medium severity vulnerability CVE-2026-23743 was detected. This vulnerability allows unauthorized users to infer sensitive information about access-restricted resources, such as private topic titles, categories, posts, or hidden tags, via permalink redirects that expose resource slugs in the redirect Location header and the 404 page search box. To address this issue, users should upgrade Discourse to versions 3.5.4, 2025.11.2, 2025.12.1 or 2026.1.0. For more details, visit https://nvd.nist.gov/vuln/detail/CVE-2026-23743.

In Discourse versions prior to 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0 a medium severity vulnerability CVE-2026-21865 was detected. This vulnerability allows moderators to improperly convert certain personal messages into public topics, bypassing intended permission restrictions. To address this issue, users should upgrade Discourse to versions 3.5.4, 2025.11.2, 2025.12.1 or 2026.1.0. For more details, visit https://nvd.nist.gov/vuln/detail/CVE-2026-21865.

In Discourse versions prior to 3.5.4, 2025.11.2, 2025.12.1 and 2026.1.0 a medium severity vulnerability CVE-2025-68659 was detected. This vulnerability allows attackers to trigger an application-level denial of service by sending oversized JSON payloads to the username change endpoint (PUT /u//preferences/username), causing server delays and resource exhaustion that degrade performance for other users and services. To address this issue, users should upgrade Discourse to versions 3.5.4, 2025.11.2, 2025.12.1 or 2026.1.0. For more details, visit https://nvd.nist.gov/vuln/detail/CVE-2025-68659.

In Discourse versions prior to 3.5.4, 2025.11.2, 2025.12.1 and 2026.1.0 a high severity vulnerability CVE-2025-68479 was detected. This vulnerability allows attackers to take over subscriptions due to missing ownership checks in certain subscription-related endpoints. To address this issue, users should upgrade Discourse to versions 3.5.4, 2025.11.2, 2025.12.1 or 2026.1.0. For more details, visit https://nvd.nist.gov/vuln/detail/CVE-2025-68479.

In Discourse versions prior to 3.5.4, 2025.11.2, 2025.12.1 and 2026.1.0 a medium severity vulnerability CVE-2025-67723 was detected. This vulnerability allows stored Cross-Site Scripting (XSS) attacks via the Discourse Math plugin when using the KaTeX renderer, despite content security policy mitigations. To address this issue, users should upgrade Discourse to versions 3.5.4, 2025.11.2, 2025.12.1 or 2026.1.0. For more details, visit https://nvd.nist.gov/vuln/detail/CVE-2025-67723.

In Discourse versions prior to 3.5.4, 2025.11.2, 2025.12.1 and 2026.1.0 a medium severity vulnerability CVE-2025-66488 was detected. This vulnerability affects installations using Amazon S3 for uploads and allows scripts to be executed in the context of the S3 or CDN domain due to improper handling of uploaded HTML or XML files. To address this issue, users should upgrade Discourse to versions 3.5.4, 2025.11.2, 2025.12.1 or 2026.1.0. For more details, visit https://nvd.nist.gov/vuln/detail/CVE-2025-66488.

In Discourse versions prior to 3.5.3, 2025.11.1 and 2025.12.0 a medium severity vulnerability CVE-2025-64528 was detected. This vulnerability allows attackers to discover user identities by searching for partial usernames, even when the enable_names setting is disabled, potentially exposing private user information through the UI or API. To address this issue, users should upgrade Discourse to versions 3.5.3, 2025.11.1, 2025.12.0 or later. For more details, visit https://nvd.nist.gov/vuln/detail/CVE-2025-64528.

In Mattermost versions 11.1.x ≤ 11.1.0, 11.0.x ≤ 11.0.5, 10.12.x ≤ 10.12.3 and 10.11.x ≤ 10.11.7 a medium severity vulnerability CVE-2025-64641 was detected. This vulnerability allows attackers to exfiltrate Jira issue data by crafting malicious post actions that abuse the share-issue-publicly endpoint, due to insufficient validation that such actions originate from the official Jira plugin. To address this issue, users should upgrade Mattermost to versions 11.2.0, 11.1.1, 11.0.6, 10.12.4, 10.11.8 or later. For more details, visit https://nvd.nist.gov/vuln/detail/CVE-2025-64641.