What is the CVSS score of CVE-2026-26265?

CVE-2026-26265 has a CVSS 3.1 base score of 7.5 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. EPSS exploitation probability: 0.0%.

Is there a public PoC exploit available for CVE-2026-26265?

Yes, a public proof-of-concept exploit is available for CVE-2026-26265. Prioritise patching immediately. EPSS: 0.0%.

How to fix or mitigate CVE-2026-26265?

Within 24 hours: Disable the directory feature or restrict access to authenticated users only; notify legal and compliance teams of potential data exposure. Within 7 days: Audit access logs to identify unauthorized data retrieval; notify affected users if private fields were exposed; evaluate alternative discussion platforms if mitigation is insufficient. Within 30 days: Upgrade to patched versions (2025.12.2, 2026.1.1, or 2026.2.0) once available; implement rate limiting and access controls on directory endpoints; conduct a full data exposure assessment.

Discourse CVE-2026-26265

HIGH

Incorrect Authorization (CWE-863)

2026-02-26 security-advisories@github.com

Authentication Bypass Information Disclosure Discourse

7.5

CVSS 3.1 · GitHub Advisory

View

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

Access

Send GET request to directory items endpoint
Exploit

Inject arbitrary user_field_ids parameter
Execution

Bypass authorization checks
Impact

Retrieve private user field values

Vulnerability Assessment

Weakness	CWE CWE-863 OWASP Top 10:2025 A01:2025 - Broken Access Control ASVS 5.0 V8 - Authorization Authorization logic validation MITRE ATT&CK 1 technique across 1 tactic: Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Exploitation Conditions	No special conditions — remote unauthenticated exploitation against Discourse versions prior to 2025.12.2, 2026.1.1, and 2026.2.0 with directory functionality enabled.
Impact	CVSS 7.5 (HIGH). Attack vector: Network. Complexity: Low. Privileges required: None. User interaction: None. Exploitation no authentication required.
Exploit ScenarioDerived	An attacker without authentication could exploit this vulnerability to compromise the affected system.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).

No patch listed yet 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

Discourse versions prior to 2025.12.2, 2026.1.1, and 2026.2.0 contain an insecure direct object reference (IDOR) in the directory items endpoint that allows unauthenticated attackers to retrieve private user field values for all directory users. The vulnerability stems from missing authorization checks on the user_field_ids parameter, enabling bulk exfiltration of sensitive user data that should be restricted by visibility settings. No patch is currently available for affected deployments.

Earlier versions of this analysis (1)

v1 Mar 12, 2026 - 21:55 CVSS 7.5

RemediationAI

Monitor vendor advisories for a patch. Restrict network access to the affected service where possible.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

Classified as CWE-863 (Incorrect Authorization). Affects the directory items component of Discourse. Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, an IDOR vulnerability in the directory items endpoint allows any user, including anonymous users, to retrieve private user field values for all users in the directory. The user_field_ids parameter in DirectoryItemsController#index accepts arbitrary user field IDs without authorization checks, bypassing the visibility restrictions (show_on_profile / show_on_user_card) that are enforced el

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

GitHub Advisory PRIMARY 7.5 HIGH

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

DescriptionGitHub Advisory

Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, an IDOR vulnerability in the directory items endpoint allows any user, including anonymous users, to retrieve private user field values for all users in the directory. The user_field_ids parameter in DirectoryItemsController#index accepts arbitrary user field IDs without authorization checks, bypassing the visibility restrictions (show_on_profile / show_on_user_card) that are enforced elsewhere (e.g., UserCardSerializer via Guardian#allowed_user_field_ids). An attacker can request GET /directory_items.json?period=all&user_field_ids=<id> with any private field ID and receive that field's value for every user in the directory response. This enables bulk exfiltration of private user data such as phone numbers, addresses, or other sensitive custom fields that admins have explicitly configured as non-public. The issue is patched in versions 2025.12.2, 2026.1.1, and 2026.2.0 by filtering user_field_ids against UserField.public_fields for non-staff users before building the custom field map. As a workaround, site administrators can remove sensitive data from private user fields, or disable the user directory via the enable_user_directory site setting.

Executive ViewAI

Why It Matters

An insecure direct object reference (IDOR) vulnerability in Discourse allows unauthorized access to private user field values for all directory users, including by unauthenticated attackers. This exposes sensitive personal information across your entire user base and creates potential compliance violations under GDPR, CCPA, and similar regulations.

Business Impact: High

Compensating Controls

Immediately disable the directory feature or restrict it to authenticated users only; implement WAF rules to block or rate-limit directory item endpoint requests from unauthenticated sources; segment the Discourse instance behind additional authentication layers; monitor and log all directory endpoint access; consider masking or removing sensitive user fields from directory visibility until patched.

Threat Intelligence Overview

EPSS Score

0.0%

Top 87% exploitable

Exploit

POC

Public exploit code exists

Data Quality

4 sources

Confidence: Medium

NVD

CVE.org

EPSS POC (1)

GitHub

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity HIGH

CISA KEV No

Public POC Yes

EPSS 0.0%

Patch available No

Active threat No

Deciding rule

HIGH severity (CVSS 7.0-8.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Scheduled

Exploitation· derived

Poc

System Exposure· derived

Open

Automatable· derived

Yes

Human Impact

High

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +38

PoC: +20

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Authentication Bypass CRITICAL

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

Information Disclosure MEDIUM

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.