Discourse has authentication bypass vulnerability in the Patreon plugin webhook endpoint
Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, when the `patreon_webhook_secret` site setting is blank, an attacker can forge valid webhook signatures by computing an HMAC-MD5 with an empty string as the key. Since the request body is known to the sender, the attacker can produce a matching signature and send arbitrary webhook payloads. This allows unauthorized creation, modification, or deletion of Patreon pledge data and triggering patron-to-group synchronization. This vulnerability is patched in versions 2025.12.2, 2026.1.1, and 2026.2.0. The fix rejects webhook requests when the webhook secret is not configured, preventing signature forgery with an empty key. As a workaround, configure the `patreon_webhook_secret` site setting with a strong, non-empty secret value. When the secret is non-empty, an attacker cannot forge valid signatures without knowing the secret.
- Published
- Feb 26, 2026
- Updated
- Jun 17, 2026
- EPSS
- 0.4% · 31th percentile
- CWE
- CWE-639
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Report tools
Action score
30
Monitor
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.4%
CISA SSVC decision
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · GitHub_M
- 7.5
- NVD has not scored this yet; the score shown is the CNA’s.
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpAffected systems
| Vendor | Product | CPE |
|---|---|---|
| discourse | discourse | cpe:2.3:a:discourse:discourse |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- discourse discoursebefore 2025.12.0
- discourse discourse2026.1.0 and later · before 2026.1.1
- discourse discourse2026.2.0
Versions reported by the vendor
Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.
discourse discourse
- < 2025.12.2, >= 2026.1.0-latest, < 2026.1.1, >= 2026.2.0-latest, < 2026.2.0affected
Same product
discourse: all recordsOther highest-scoring records for the same primary product.
- CVE-2021-41163RCE via malicious SNS subscription payload45Plan
- CVE-2025-68662FinalDestination hostname matching allows SSRF protection bypass39Monitor
- CVE-2023-47121Discourse SSRF vulnerability in Embedding39Monitor
- CVE-2026-55674Discourse: Cache poisoning/XSS via color scheme cookies37Monitor
- CVE-2026-53963Discourse: Stored-XSS in 2FA delete confirmation modal36Monitor
- CVE-2024-49765Bypass of Discourse Connect using other login paths if enabled in Discourse36Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2026-3211422 days apartDiscourse's unscoped status lookups leak restricted metadata21Monitor
- CVE-2026-72724165 days apartDiscourse: Private Chat Threat Message Disclosure via Chat Onebox Channel/Threat ID Mismatch17Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
- CVE-2025-6866229 days apartFinalDestination hostname matching allows SSRF protection bypass39Monitor
- CVE-2026-45775106 days apartDiscourse: Cross-site backup access via path traversal in multisite local backups27Monitor
- CVE-2026-3318533 days apartDiscourse: Group SMTP test endpoint susceptible to SSRF21Monitor
- CVE-2026-271490 days apartDiscourse has SQL injection in PM tag filtering19Monitor
Bug bounty scope
The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- high · data or configuration can be modified
- Availability
- none
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- High
- Availability impact
- None
Weakness class (CWE)
CWE-639 · Authorization Bypass Through User-Controlled KeyCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
nvd-secondary
Root cause
The endpoint fetches the record by the ID sent in the request, but never checks whether the record belongs to the requesting user.
The bug in code
The whole CWE-639 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
const invoice = await Invoice.findById(req.params.id);res.json(invoice);Fixed
const invoice = await Invoice.findOne({ id: req.params.id, ownerId: req.user.id,});if (!invoice) return res.sendStatus(404);res.json(invoice);Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.