FKIE_CVE-2026-26973
Vulnerability from fkie_nvd - Published: 2026-02-26 20:31 - Updated: 2026-06-17 10:26
Severity
Summary
Discourse is an open source discussion platform. Versions prior to 2025.12.2, 2026.1.1, and 2026.2.0 have an IDOR (Insecure Direct Object Reference) in `ReviewableNotesController`. When `enable_category_group_moderation` is enabled, a user belonging to a category moderation group can create or delete their own notes on **any** reviewable in the system, including reviewables in categories they do not moderate. The controller used an unscoped `Reviewable.find` and the `ensure_can_see` guard only checked whether the user could access the review queue in general, not whether they could access the specific reviewable. Only instances with `enable_category_group_moderation` enabled are affected. Staff users (admins/moderators) are not impacted as they already have access to all reviewables. The issue is patched in versions 2025.12.2, 2026.1.1, and 2026.2.0 by scoping the reviewable lookup through `Reviewable.viewable_by(current_user)`. As a workaround, disable the `enable_category_group_moderation` site setting. This removes the attack surface as only staff users will have access to the review queue.
References
{
"affected": [
{
"affectedData": [
{
"product": "discourse",
"vendor": "discourse",
"versions": [
{
"status": "affected",
"version": "\u003c 2025.12.2"
},
{
"status": "affected",
"version": "\u003e= 2026.1.0-latest, \u003c 2026.1.1"
},
{
"status": "affected",
"version": "\u003e= 2026.2.0-latest, \u003c 2026.2.0"
}
]
}
],
"source": "security-advisories@github.com"
}
],
"configurations": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*",
"matchCriteriaId": "6DB837D7-28C8-4E0F-B55F-AAAA36F32035",
"versionEndExcluding": "2025.12.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*",
"matchCriteriaId": "1CAFCC9D-53D7-4017-85A5-EE6CA5A6A11C",
"versionEndExcluding": "2026.1.1",
"versionStartIncluding": "2026.1.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:discourse:discourse:2026.2.0:*:*:*:latest:*:*:*",
"matchCriteriaId": "BB002FDC-BC71-4C46-8AAF-A34EC717E0E7",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "Discourse is an open source discussion platform. Versions prior to 2025.12.2, 2026.1.1, and 2026.2.0 have an IDOR (Insecure Direct Object Reference) in `ReviewableNotesController`. When `enable_category_group_moderation` is enabled, a user belonging to a category moderation group can create or delete their own notes on **any** reviewable in the system, including reviewables in categories they do not moderate. The controller used an unscoped `Reviewable.find` and the `ensure_can_see` guard only checked whether the user could access the review queue in general, not whether they could access the specific reviewable. Only instances with `enable_category_group_moderation` enabled are affected. Staff users (admins/moderators) are not impacted as they already have access to all reviewables. The issue is patched in versions 2025.12.2, 2026.1.1, and 2026.2.0 by scoping the reviewable lookup through `Reviewable.viewable_by(current_user)`. As a workaround, disable the `enable_category_group_moderation` site setting. This removes the attack surface as only staff users will have access to the review queue."
},
{
"lang": "es",
"value": "Discourse es una plataforma de discusi\u00f3n de c\u00f3digo abierto. Versiones anteriores a 2025.12.2, 2026.1.1 y 2026.2.0 tienen una IDOR (Referencia Directa Insegura a Objeto) en `ReviewableNotesController`. Cuando `enable_category_group_moderation` est\u00e1 habilitado, un usuario que pertenece a un grupo de moderaci\u00f3n de categor\u00eda puede crear o eliminar sus propias notas en cualquier elemento revisable del sistema, incluyendo elementos revisables en categor\u00edas que no modera. El controlador us\u00f3 un `Reviewable.find` sin \u00e1mbito y la protecci\u00f3n `ensure_can_see` solo verificaba si el usuario pod\u00eda acceder a la cola de revisi\u00f3n en general, no si pod\u00eda acceder al elemento revisable espec\u00edfico. Solo las instancias con `enable_category_group_moderation` habilitado se ven afectadas. Los usuarios del personal (administradores/moderadores) no se ven afectados ya que ya tienen acceso a todos los elementos revisables. El problema est\u00e1 parcheado en las versiones 2025.12.2, 2026.1.1 y 2026.2.0 al limitar la b\u00fasqueda de elementos revisables a trav\u00e9s de `Reviewable.viewable_by(current_user)`. Como soluci\u00f3n alternativa, deshabilite la configuraci\u00f3n del sitio `enable_category_group_moderation`. Esto elimina la superficie de ataque ya que solo los usuarios del personal tendr\u00e1n acceso a la cola de revisi\u00f3n."
}
],
"id": "CVE-2026-26973",
"lastModified": "2026-06-17T10:26:28.087",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 4.3,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "LOW",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N",
"version": "3.1"
},
"exploitabilityScore": 2.8,
"impactScore": 1.4,
"source": "security-advisories@github.com",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-26973",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-02-26T20:40:10.083850Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-02-26T20:31:37.327",
"references": [
{
"source": "security-advisories@github.com",
"tags": [
"Vendor Advisory"
],
"url": "https://github.com/discourse/discourse/security/advisories/GHSA-c587-qx78-vhmx"
}
],
"sourceIdentifier": "security-advisories@github.com",
"vulnStatus": "Analyzed",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-863"
}
],
"source": "security-advisories@github.com",
"type": "Secondary"
},
{
"description": [
{
"lang": "en",
"value": "CWE-639"
}
],
"source": "nvd@nist.gov",
"type": "Primary"
}
]
}
Loading…
Loading…
Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.
Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline
Sightings and recorded dates, grouped by day · UTC
How durations are calculated
Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.
Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.
Loading timeline…
Loading…
Loading…
The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Loading…
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.