What is the CVSS score of EUVD-2026-42735?

EUVD-2026-42735 has a CVSS 3.1 base score of 7.1 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N. EPSS exploitation probability: 0.3%.

How to fix or mitigate EUVD-2026-42735?

Within 24 hours, identify all Discourse installations in your environment and confirm which have whispers_allowed_groups enabled, as only those configurations face risk. Within 7 days, apply the vendor-released patch per GHSA-vmwq-jvxx-jwfx advisory to all affected instances, prioritizing production deployments. Within 30 days, audit whisper-group access logs for indicators of unauthorized access and verify patching completion across your Discourse fleet.

Discourse EUVD-2026-42735

Q: Which versions of Discourse are affected by EUVD-2026-42735?

Discourse installations with whisper-group functionality are vulnerable to CVE-2026-44787, a privilege escalation flaw allowing newly registered users unauthorized access to staff-only confidential…. A patch is available.

| CVE-2026-44787 HIGH

Improper Privilege Management (CWE-269)

2026-07-09 security-advisories@github.com

Privilege Escalation Discourse

7.1

CVSS 3.1 · NVD

View

Attack ChainAIDerived

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

Access

Register account via public signup endpoint
Delivery

Inject primary_group_id of whisper-allowed group
Exploit

Server saves primary_group_id without membership check
Execution

whisperer? evaluates true
Impact

Read/post staff-only whisper content

Vulnerability Assessment

Weakness	CWE CWE-269 OWASP Top 10:2025 A06:2025 - Insecure Design ASVS 5.0 V8 - Authorization Least privilege enforcement 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	Exploitation requires the target Discourse site to have the whispers_allowed_groups site setting configured - a non-default, opt-in staff feature; without it, injecting primary_group_id grants no whisper privilege and the bug is inert. The attacker must complete the signup flow while submitting primary_group_id (and optionally flair_group_id) pointing at an allowed group; the fix's regression test shows this was accepted on the unauthenticated signup request, so no pre-existing account or elevated role is needed. Limiting factors: impact is confined to whisper (staff-visible) content confidentiality with only minor integrity effect and no availability impact, and any site without whispers_allowed_groups is unaffected regardless of other configuration.
Impact	The signals are largely consistent and point to a real but moderate-priority issue rather than an emergency. The input CVSS 3.1 vector (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N, 7.1 High) reflects network-reachable, low-complexity exploitation with confidentiality-heavy impact. SSVC agrees on 'partial' technical impact and 'automatable: yes' (the signup request is scriptable), but marks Exploitation as 'none', matching the low EPSS (0.31%) and the absence of any KEV listing or known public exploit code. The key caveat the raw CVSS omits is a configuration gate: the flaw only has security impact where whispers_allowed_groups is set, so the realistically-affected population is a subset of all Discourse installs. There is also a metrics tension - the patch's regression tests demonstrate the injection succeeding on the unauthenticated signup request, which argues the true privilege requirement is closer to PR:N than the PR:L given in the input.
Exploit ScenarioDerived	On a Discourse forum that has enabled group-based whispers, an attacker scripts the public registration endpoint and includes primary_group_id set to the ID of a whisper-allowed group in the signup payload. Once the account is created, the attacker is treated as a whisperer and can read (and post) staff-only whisper content that should be hidden from ordinary members. No public exploit is identified at time of analysis, but the request is simple and automatable per SSVC.

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

Patch available 0.3% exploitation probability (EPSS)

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AnalysisAIv2 – Jul 14, 2026

Privilege escalation in Discourse (the open-source discussion platform) lets a newly registered user obtain whisper-group ('whisperer') privileges by supplying a primary_group_id during the signup flow, without ever being a legitimate member of that group. Exploitation only matters on sites that have configured whispers_allowed_groups, and success grants read access to staff-only whisper posts (a confidentiality-focused impact). EPSS is low (0.31%, 23rd percentile) and there is no public exploit identified at time of analysis, but the fix commits and GitHub advisory GHSA-vmwq-jvxx-jwfx confirm the flaw and its remediation.

Earlier versions of this analysis (1)

v1 Jul 09, 2026 - 22:31 CVSS 8.2

Privilege escalation in Discourse (versions prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5) lets a newly self-registered user assign themselves a primary_group_id during the signup flow and inherit whisper-group privileges without ever being a legitimate member of that group, but only on instances that have whispers_allowed_groups configured. Because whispers are private staff/group-only messages, an attacker gains unauthorized read access to confidential moderator discussions. There is no public exploit identified at time of analysis and it is not listed in CISA KEV, though the GitHub Security Advisory (GHSA-vmwq-jvxx-jwfx) and four fix commits are public, lowering the bar to reverse-engineer the flaw.

RemediationAI

Vendor-released patch: upgrade to Discourse 2026.6.0, 2026.5.1, 2026.4.2, or 2026.1.5 (whichever matches your release branch), available at https://github.com/discourse/discourse/releases (tags v2026.6.0, v2026.5.1, v2026.4.2, v2026.1.5). The fix strips primary_group_id and flair_group_id from non-admin/non-API signup parameters and stops treating primary_group_id alone as a source of whisper privileges. As an interim compensating control where you cannot patch immediately, temporarily clear or unset the whispers_allowed_groups site setting to neutralize the impact (trade-off: this disables group-based whisper access for legitimate staff), and audit recently created accounts for unexpected primary_group_id/flair_group_id values pointing at whisper-allowed groups, resetting any that lack genuine membership. Details are in advisory GHSA-vmwq-jvxx-jwfx and commit 012796ac28c85b30aa233c5ef042fc66efff8126.

Affected VersionsENISA

discourse 2026.5.0-latest, < 2026.5.1

discourse 2026.1.0-latest, < 2026.1.5

discourse 2026.4.0-latest, < 2026.4.2

Affected Packages

euvd discourse_2026_1_0_latest fix: 2026.1.5

euvd discourse_2026_4_0_latest fix: 2026.4.2

euvd discourse_2026_5_0_latest fix: 2026.5.1

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 3 packages in euvd

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

Technical ContextAI · show details

Discourse is a Ruby on Rails discussion/forum platform. This is a CWE-269 Improper Privilege Management issue spanning the account-creation path (UsersController#create) and the Roleable concern. Signup parameters were passed through with only :timezone stripped, letting an attacker inject :primary_group_id (and :flair_group_id). Separately, Roleable#whisperer? treated any user whose primary_group_id was contained in SiteSetting.whispers_allowed_groups_map as a whisperer, so pointing primary_group_id at an allowed group synthesized the privilege with no real membership. The CPE data (cpe:2.3:a:discourse:discourse) confirms the affected product is the Discourse application itself, with the fix landing in tagged release 2026.6.0.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (github) PRIMARY HIGH

NVD 7.1 HIGH

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

vuln.today AI 8.2 HIGH

Patch tests show injection succeeds on unauthenticated signup, so PR:N and AC:L; whisper read access drives C:H with minor I:L and no availability impact.

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

4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N

Primary rating from Vendor (github).

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

Low

Availability

None

Lifecycle Timeline

Analysis Updated

Jul 14, 2026 - 20:59 vuln.today

v2 - CVSS changed

CVSS changed

Jul 14, 2026 - 20:52 NVD

8.2 (HIGH) 7.1 (HIGH)

Patch available

Jul 09, 2026 - 23:02 EUVD

DescriptionNVD

Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, the signup flow could allow newly registered users to set primary_group_id and gain whisper-group privileges without legitimate group membership on sites with whispers_allowed_groups configured. This issue is fixed in versions 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5.

Executive ViewAI

Why It Matters

Discourse installations with whisper-group functionality are vulnerable to CVE-2026-44787, a privilege escalation flaw allowing newly registered users unauthorized access to staff-only confidential discussions. No public exploit identified at time of analysis. Affected organizations risk unauthorized disclosure of internal communications, decisions, and sensitive operational guidance to users with minimal account tenure.

Business Impact: High

Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score

0.3%

Top 77% exploitable

Prevalence

Medium

popular open-source forum platform, common but not everywhere

Social Media

Sightings

Data Quality

6 sources

Confidence: High

EUVD

NVD

CVE.org

EPSS

Vulnrichment CIRCL

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 No

EPSS 0.3%

Patch available Yes

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

Scheduled

Exploitation

None

System Exposure· derived

Open

Automatable

Yes

Human Impact

High

Technical Impact

Partial

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +36

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Privilege Escalation HIGH

Privilege escalation occurs when an attacker leverages flaws in access control mechanisms to gain permissions beyond what they were originally granted.