Cyber Resilience

CVE-2026-24742

Access Control in Discourse ≤ 3.5.4

Published
28 January 2026
Modified
30 January 2026
CVSS Score v3.1 6.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
EPSS Score 0.0026 17th percentile
Risk Priority 35 floored blend · peak EPSS

Summary

CVE-2026-24742 is a medium-severity Incorrect Authorization (CWE-863) vulnerability in Discourse Discourse. Its CVSS base score is 6.5 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Unsecured Credentials (T1552); ranked at the 17th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and AU-9 (Protection of Audit Information) — 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, non-admin moderators can view sensitive information in staff action logs that should be restricted to administrators only. The exposed information includes webhook payload URLs…

more

and secrets, API key details, site setting changes, private message content, restricted category names and structures, and private chat channel titles. This allows moderators to bypass intended access controls and extract confidential data by monitoring the staff action logs. With leaked webhook secrets, an attacker could potentially spoof webhook events to integrated services. This issue is patched in versions 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0. As a workaround, site administrators should review and limit moderator appointments to fully trusted users. There is no configuration-based workaround to prevent this access.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1552 Unsecured Credentials Credential Access
Adversaries may search compromised systems to find and obtain insecurely stored credentials.
T1213 Data from Information Repositories Collection
Adversaries may leverage information repositories to mine valuable information.
Why these techniques?

The authorization bypass directly exposes secrets (API keys, webhook credentials) and sensitive configuration data stored in audit logs, enabling unsecured credential access (T1552) and retrieval from an internal information repository (T1213).

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

CVEs Like This One

CVE-2026-27153Same product: Discourse Discourse
CVE-2025-68666Same product: Discourse Discourse
CVE-2025-68933Same product: Discourse Discourse
CVE-2023-32061Same product: Discourse Discourse
CVE-2026-33291Same product: Discourse Discourse
CVE-2025-69289Same product: Discourse Discourse
CVE-2025-69218Same product: Discourse Discourse
CVE-2026-33410Same product: Discourse Discourse
CVE-2026-33428Same product: Discourse Discourse
CVE-2026-33251Same 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
  • AU-9 Protection of Audit Information
  • 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 so that non-admin moderators cannot read administrator-only fields (webhook secrets, API keys, PM content, etc.) stored in staff action logs.

prevent

Requires protection of audit records against unauthorized access or disclosure, precisely the exposure of sensitive staff-action-log contents to moderators.

prevent

Limits moderator privileges to only the minimum required, preventing the assignment of read access to administrator-restricted log entries.

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