CVE-2026-59830

Description

Discourse is an open-source discussion platform. Prior to 2026.7.0, the post action component failed to escape user-controlled display names before interpolating them into an HTML string passed to trustHTML. A user who could choose a crafted display name could persist markup in post action descriptions. Viewing the affected user activity streams could execute attacker-controlled script in another user's browser. This issue is fixed in version 2026.7.0.

Overview

State: PUBLISHED
Assigner (CNA): GitHub_M
CVSS severity: MEDIUM
CVSS score: 5.4 / 10
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Effective score: 5.4 / 10 MEDIUM source: CNA overview
CWE(s): CWE-79
Reserved: 2026-07-07
Published: 2026-09-21 21:17 UTC
Last updated: 2026-09-21 21:17 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/59xxx/CVE-2026-59830.json

NVD triage scoring NVD CVE 2.0

Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.

NVD published: 2026-09-21 22:16:57 UTC
NVD last modified: 2026-09-21 22:16:57 UTC
NVD CVSS v3.1: 5.4 / 10 MEDIUM source: security-advisories@github.com
NVD CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Exploitability subscore: 2.3 / 10
Impact subscore: 2.7 / 10

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2026-84181
Assigner: GitHub_M
Published: Sep 21, 2026, 9:17:38 PM
Updated: Sep 21, 2026, 9:17:38 PM
EUVD base score (CVSS 3.1): 5.4 / 10
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
EUVD-reported EPSS: 0.0000
Vendors: discourse
Products: discourse (< 2026.7.0)

ENISA description: Discourse is an open-source discussion platform. Prior to 2026.7.0, the post action component failed to escape user-controlled display names before interpolating them into an HTML string passed to trustHTML. A user who could choose a crafted display name could persist markup in post action descriptions. Viewing the affected user activity streams could execute attacker-controlled script in another user's browser. This issue is fixed in version 2026.7.0.

EUVD references (3)

Affected products (1)

Vendor	Product	Versions	Platforms
discourse	discourse	`< 2026.7.0` (affected)	—

Vendor references (3)

References embedded in the original CVE record by the assigning CNA.

https://github.com/discourse/discourse/security/advisories/GHSA-x6mf-p7cg-69rw x_refsource_CONFIRM
https://github.com/discourse/discourse/commit/dd786594ddd088657a7e6f9fefba5bd889965fe4 x_refsource_MISC
https://github.com/discourse/discourse/releases/tag/v2026.7.0 x_refsource_MISC

Web references (0)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

No web references attached yet.

NVD-tagged references (3)

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

https://github.com/discourse/discourse/commit/dd786594ddd088657a7e6f9fefba5bd889965fe4 security-advisories@github.com
https://github.com/discourse/discourse/releases/tag/v2026.7.0 security-advisories@github.com
https://github.com/discourse/discourse/security/advisories/GHSA-x6mf-p7cg-69rw security-advisories@github.com

Remediations (10)

CVEs and Security Vulnerabilities - OpenCVE

web:app.opencve.io

Explore the latest vulnerabilities and security issues in the CVE database

2026-09-22 17:11 UTC
CVE-2026-59830 - Vulnerability Details - OpenCVE

web:app.opencve.io

Discourse is an open-source discussion platform. Prior to 2026.7.0, the post action component failed to escape user-controlled display names before interpolating them into an HTML string passed to trustHTML. A user who could choose a crafted display name could persist markup in post action descriptions. Viewing the affected user activity streams could execute attacker-controlled script in ...

2026-09-22 17:11 UTC
CVE-2026-59830 | Vulnerability Database | Aqua Security

web:avd.aquasec.com

CVE-2026-59830 Vulnerability, Severity 0 N/A, Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

2026-09-22 17:11 UTC
VMware Telco Cloud response to VMSA-2026-0006 (CVE-2026-59309, CVE-2026 ...

web:knowledge.broadcom.com

VMware Telco Cloud response to VMSA- 2026 -0006 ( CVE - 2026 -59309, CVE - 2026 -59310, CVE - 2026 -47876, CVE - 2026 -41703, CVE - 2026 -41709) Patch Availability for VMware Telco Cloud Platform / Telco Cloud Infrastructure

2026-09-22 17:11 UTC
OWASP Juice Shop | OWASP Foundation

web:owasp.org

OWASP Juice Shop is probably the most modern and sophisticated insecure web application! It can be used in security trainings, awareness demos, CTFs and as a guinea pig for security tools! Juice Shop encompasses vulnerabilities from the entire OWASP Top Ten along with many other security flaws found in real-world applications! Description Juice Shop is written in Node.js, Express and Angular ...

2026-09-22 17:11 UTC
Cisco Advance Notification for Publication of September 16, 2026 ...

web:sec.cloudapps.cisco.com

On September 16, 2026 , the Cisco Product Security Incident Response Team (PSIRT) published the advisories that are listed in the following tables. To remediate these vulnerabilities, Cisco strongly recommends that customers upgrade to the fixed software that is indicated in the advisories. For more information about changes in Cisco PSIRT vulnerability disclosure, see Strengthening the ...

2026-09-22 17:11 UTC
CVE-2026-59830 - Discourse Post Action Component XSS via…

web:vulmon.com

Vulnerability Summary Discourse is an open-source discussion platform. before 2026.7.0, the post action component failed to escape user-controlled display names before interpolating them into an HTML string passed to trustHTML. A user who could choose a crafted display name could persist markup in post action descriptions. Viewing the affected user activity streams could execute attacker ...

2026-09-22 17:11 UTC
Oracle Critical Patch Update Advisory - April 2026

web:www.oracle.com

This Critical Patch Update contains 481 new security patches across the product families listed below. Please note that an MOS note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at April 2026 Critical Patch Update: Executive Summary and Analysis.

2026-09-22 17:11 UTC
Oracle Critical Patch Update Advisory - July 2026

web:www.oracle.com

This Critical Patch Update contains 1448 new security patches across the product families listed below. Please note that a My Oracle Support (MOS) note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at July 2026 Critical Patch Update: Executive Summary and Analysis.

2026-09-22 17:11 UTC
CVE-2026-59830: discourse: Discourse is an open-source ... - Rapid7

web:www.rapid7.com

CVE-2026-59830 : discourse: Discourse is an open-source discussion platform. View severity, references, and remediation details from Rapid7.

2026-09-22 17:11 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-59830.json.

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "discourse",
          "vendor": "discourse",
          "versions": [
            {
              "status": "affected",
              "version": "< 2026.7.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Discourse is an open-source discussion platform. Prior to 2026.7.0, the post action component failed to escape user-controlled display names before interpolating them into an HTML string passed to trustHTML. A user who could choose a crafted display name could persist markup in post action descriptions. Viewing the affected user activity streams could execute attacker-controlled script in another user's browser. This issue is fixed in version 2026.7.0."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 5.4,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "scope": "CHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-79",
              "description": "CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-21T21:17:38.733Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/discourse/discourse/security/advisories/GHSA-x6mf-p7cg-69rw",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/discourse/discourse/security/advisories/GHSA-x6mf-p7cg-69rw"
        },
        {
          "name": "https://github.com/discourse/discourse/commit/dd786594ddd088657a7e6f9fefba5bd889965fe4",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/discourse/discourse/commit/dd786594ddd088657a7e6f9fefba5bd889965fe4"
        },
        {
          "name": "https://github.com/discourse/discourse/releases/tag/v2026.7.0",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/discourse/discourse/releases/tag/v2026.7.0"
        }
      ],
      "source": {
        "advisory": "GHSA-x6mf-p7cg-69rw",
        "discovery": "UNKNOWN"
      },
      "title": "Discourse: Stored XSS via unescaped actor name in post actions"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-59830",
    "datePublished": "2026-09-21T21:17:38.733Z",
    "dateReserved": "2026-07-07T15:00:50.979Z",
    "dateUpdated": "2026-09-21T21:17:38.733Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}