Cyber Resilience

CVE-2025-68660

Access Control in Discourse ≤ 3.5.4

Published
28 January 2026
Modified
30 January 2026
CVSS Score v4 5.3
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0022 12th percentile
Risk Priority 35 floored blend · peak EPSS

Summary

CVE-2025-68660 is a medium-severity Incorrect Authorization (CWE-863) vulnerability in Discourse Discourse. Its CVSS base score is 5.3 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 12th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

This vulnerability is AI-related — categorised as Enterprise AI Assistants; in the Privacy and Disclosure risk domain.

The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and AC-4 (Information Flow Enforcement) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

Discourse is an open source discussion platform. In versions prior to 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0, an endpoint lets any authenticated user bypass the ai_discover_persona access controls and gain ongoing DM access to personas that may be wired to staff-only…

more

categories, RAG document sets, or automated tooling, enabling unauthorized data disclosure. Because the controller also accepts arbitrary user_id, an attacker can impersonate other accounts to trigger unwanted AI conversations on their behalf, generating confusing or abusive PM traffic. This issue is patched in versions 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0. No known workarounds are available.

CWE(s)

AI Security AnalysisAI

AI Category
Enterprise AI Assistants
Risk Domain
Privacy and Disclosure
OWASP Top 10 for LLMs 2025
None mapped
Classification Reason
Matched keywords: ai

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1213 Data from Information Repositories Collection
Adversaries may leverage information repositories to mine valuable information.
T1534 Internal Spearphishing Lateral Movement
After they already have access to accounts or systems within the environment, adversaries may use internal spearphishing to gain access to additional information or compromise other users within the same organization.
Why these techniques?

Authorization bypass on authenticated endpoint directly enables exploitation of public-facing app (T1190) to reach restricted RAG/categories (T1213) and impersonate users for abusive messaging (T1534).

Confidence: MEDIUM · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2025-68666Same product: Discourse Discourse
CVE-2026-33428Same product: Discourse Discourse
CVE-2026-33251Same product: Discourse Discourse
CVE-2026-27153Same product: Discourse Discourse
CVE-2026-33424Same product: Discourse Discourse
CVE-2026-27936Same product: Discourse Discourse
CVE-2025-68933Same product: Discourse Discourse
CVE-2026-24742Same product: Discourse Discourse
CVE-2026-28282Same product: Discourse Discourse
CVE-2026-28227Same product: Discourse Discourse

Affected Assets

discourse
discourse
2025.12.0, 2026.1.0 · ≤ 3.5.4 · 2025.11.0 — 2025.11.2

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • AC-3 Access Enforcement
  • AC-4 Information Flow Enforcement
  • AC-6 Least Privilege
Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 5 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)

Mitigating Controls (NIST 800-53 r5) AI

prevent

Directly enforces authorization checks on the ai_discover_persona endpoint and user_id parameter to block the described bypass and impersonation.

prevent

Enforces information flow rules between users, personas, staff-only categories and RAG data sets that the vulnerable endpoint currently violates.

prevent

Limits privileges so ordinary authenticated accounts cannot reach staff-wired personas or act on arbitrary user_ids even if the check is missing.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-05 mostly match
prevents

Defining, enforcing, and reviewing access authorizations and least privilege directly prevents incorrect authorization checks.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

prevents

Requiring consistency between access rights and classification plus formal approval steps ensures that the authorization logic correctly distinguishes between entities that should and should not be granted access.

prevents

Enforcing policy-driven approval and role-change reviews stops incorrect or stale authorization decisions from remaining in effect after job changes or terminations.

prevents

By tying access rights to identity, device, location and classification, the control reduces the likelihood that an authorization decision will be based on an incorrect or bypassed policy.

References