CVE-2026-27154 (GCVE-0-2026-27154)
Vulnerability from cvelistv5 – Published: 2026-02-26 21:20 – Updated: 2026-02-26 21:20
VLAI?
Title
Discourse has XSS when editing a malicious post
Summary
Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, a user full name can be evaluated as raw HTML when the following settings are set: `display_name_on_posts` => true; and `prioritize_username_in_ux` => false. Editing a post of a malicious user would trigger an XSS. Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. No known workarounds are available.
Severity ?
CWE
- CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Assigner
References
| URL | Tags | ||||
|---|---|---|---|---|---|
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Impacted products
{
"containers": {
"cna": {
"affected": [
{
"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"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, a user full name can be evaluated as raw HTML when the following settings are set: `display_name_on_posts` =\u003e true; and `prioritize_username_in_ux` =\u003e false. Editing a post of a malicious user would trigger an XSS. Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. No known workarounds are available."
}
],
"metrics": [
{
"cvssV4_0": {
"attackComplexity": "LOW",
"attackRequirements": "NONE",
"attackVector": "NETWORK",
"baseScore": 1.3,
"baseSeverity": "LOW",
"privilegesRequired": "LOW",
"subAvailabilityImpact": "NONE",
"subConfidentialityImpact": "LOW",
"subIntegrityImpact": "LOW",
"userInteraction": "NONE",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U",
"version": "4.0",
"vulnAvailabilityImpact": "NONE",
"vulnConfidentialityImpact": "NONE",
"vulnIntegrityImpact": "NONE"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-79",
"description": "CWE-79: Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027)",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-02-26T21:20:25.181Z",
"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"shortName": "GitHub_M"
},
"references": [
{
"name": "https://github.com/discourse/discourse/security/advisories/GHSA-xv43-5gcp-wgw8",
"tags": [
"x_refsource_CONFIRM"
],
"url": "https://github.com/discourse/discourse/security/advisories/GHSA-xv43-5gcp-wgw8"
}
],
"source": {
"advisory": "GHSA-xv43-5gcp-wgw8",
"discovery": "UNKNOWN"
},
"title": "Discourse has XSS when editing a malicious post"
}
},
"cveMetadata": {
"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"assignerShortName": "GitHub_M",
"cveId": "CVE-2026-27154",
"datePublished": "2026-02-26T21:20:25.181Z",
"dateReserved": "2026-02-18T00:18:53.962Z",
"dateUpdated": "2026-02-26T21:20:25.181Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"nvd": "{\"cve\":{\"id\":\"CVE-2026-27154\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-02-26T22:20:47.730\",\"lastModified\":\"2026-02-27T14:06:37.987\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, a user full name can be evaluated as raw HTML when the following settings are set: `display_name_on_posts` =\u003e true; and `prioritize_username_in_ux` =\u003e false. Editing a post of a malicious user would trigger an XSS. Versions 2025.12.2, 2026.1.1, and 2026.2.0 patch the issue. No known workarounds are available.\"},{\"lang\":\"es\",\"value\":\"Discourse es una plataforma de discusi\u00f3n de c\u00f3digo abierto. Antes de las versiones 2025.12.2, 2026.1.1 y 2026.2.0, el nombre completo de un usuario puede ser evaluado como HTML sin procesar cuando las siguientes configuraciones est\u00e1n establecidas: \u0027display_name_on_posts\u0027 =\u0026gt; true; y \u0027prioritize_username_in_ux\u0027 =\u0026gt; false. Editar una publicaci\u00f3n de un usuario malicioso activar\u00eda un XSS. Las versiones 2025.12.2, 2026.1.1 y 2026.2.0 parchean el problema. No hay soluciones alternativas conocidas disponibles.\"}],\"metrics\":{\"cvssMetricV40\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"4.0\",\"vectorString\":\"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X\",\"baseScore\":1.3,\"baseSeverity\":\"LOW\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"attackRequirements\":\"NONE\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"vulnConfidentialityImpact\":\"NONE\",\"vulnIntegrityImpact\":\"NONE\",\"vulnAvailabilityImpact\":\"NONE\",\"subConfidentialityImpact\":\"LOW\",\"subIntegrityImpact\":\"LOW\",\"subAvailabilityImpact\":\"NONE\",\"exploitMaturity\":\"UNREPORTED\",\"confidentialityRequirement\":\"NOT_DEFINED\",\"integrityRequirement\":\"NOT_DEFINED\",\"availabilityRequirement\":\"NOT_DEFINED\",\"modifiedAttackVector\":\"NOT_DEFINED\",\"modifiedAttackComplexity\":\"NOT_DEFINED\",\"modifiedAttackRequirements\":\"NOT_DEFINED\",\"modifiedPrivilegesRequired\":\"NOT_DEFINED\",\"modifiedUserInteraction\":\"NOT_DEFINED\",\"modifiedVulnConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedVulnIntegrityImpact\":\"NOT_DEFINED\",\"modifiedVulnAvailabilityImpact\":\"NOT_DEFINED\",\"modifiedSubConfidentialityImpact\":\"NOT_DEFINED\",\"modifiedSubIntegrityImpact\":\"NOT_DEFINED\",\"modifiedSubAvailabilityImpact\":\"NOT_DEFINED\",\"Safety\":\"NOT_DEFINED\",\"Automatable\":\"NOT_DEFINED\",\"Recovery\":\"NOT_DEFINED\",\"valueDensity\":\"NOT_DEFINED\",\"vulnerabilityResponseEffort\":\"NOT_DEFINED\",\"providerUrgency\":\"NOT_DEFINED\"}}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-79\"}]}],\"references\":[{\"url\":\"https://github.com/discourse/discourse/security/advisories/GHSA-xv43-5gcp-wgw8\",\"source\":\"security-advisories@github.com\"}]}}"
}
}
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Sightings
| Author | Source | Type | Date |
|---|
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.
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