CVE-2026-72723 (GCVE-0-2026-72723)
Vulnerability from cvelistv5 – Published: 2026-08-10 15:56 – Updated: 2026-08-10 21:11
VLAI
EPSS
VEX
Title
Discourse: Anonymous sidebar serialization exposes descriptions of category-restricted tags
Summary
Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, SiteSerializer.anonymous_default_navigation_menu_tags serializes tags from SiteSetting.default_navigation_menu_tags without applying DiscourseTagging.filter_visible for the anonymous viewer. An unauthenticated user can retrieve restricted tag names and descriptions through /site.json when those tags are limited by inaccessible categories, category tag groups, or tag-group permissions. This issue is fixed in versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0.
Severity
5.3 (Medium)
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-10 19:02 UTC
CWE
- CWE-862 - Missing Authorization
Assigner
References
9 references
| URL | Tags |
|---|---|
| https://github.com/discourse/discourse/security/a… | x_refsource_CONFIRM |
| https://github.com/discourse/discourse/pull/42091 | x_refsource_MISC |
| https://github.com/discourse/discourse/pull/42092 | x_refsource_MISC |
| https://github.com/discourse/discourse/pull/42093 | x_refsource_MISC |
| https://github.com/discourse/discourse/pull/42094 | x_refsource_MISC |
| https://github.com/discourse/discourse/commit/024… | x_refsource_MISC |
| https://github.com/discourse/discourse/commit/034… | x_refsource_MISC |
| https://github.com/discourse/discourse/commit/900… | x_refsource_MISC |
| https://github.com/discourse/discourse/commit/da8… | x_refsource_MISC |
Impacted products
{
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{
"metrics": [
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"options": [
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"version": "2.0.3"
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"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
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{
"product": "discourse",
"vendor": "discourse",
"versions": [
{
"status": "affected",
"version": "\u003c 2026.1.6"
},
{
"status": "affected",
"version": "\u003e= 2026.5.0-latest, \u003c 2026.5.2"
},
{
"status": "affected",
"version": "\u003e= 2026.6.0-latest, \u003c 2026.6.1"
},
{
"status": "affected",
"version": "\u003e= 2026.7.0-latest, \u003c 2026.7.0"
}
]
}
],
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"lang": "en",
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}
],
"metrics": [
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"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 5.3,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "LOW",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
"version": "3.1"
}
}
],
"problemTypes": [
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"cweId": "CWE-862",
"description": "CWE-862: Missing Authorization",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-10T15:56:53.723Z",
"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"shortName": "GitHub_M"
},
"references": [
{
"name": "https://github.com/discourse/discourse/security/advisories/GHSA-4p6q-h74v-5j7p",
"tags": [
"x_refsource_CONFIRM"
],
"url": "https://github.com/discourse/discourse/security/advisories/GHSA-4p6q-h74v-5j7p"
},
{
"name": "https://github.com/discourse/discourse/pull/42091",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/discourse/discourse/pull/42091"
},
{
"name": "https://github.com/discourse/discourse/pull/42092",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/discourse/discourse/pull/42092"
},
{
"name": "https://github.com/discourse/discourse/pull/42093",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/discourse/discourse/pull/42093"
},
{
"name": "https://github.com/discourse/discourse/pull/42094",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/discourse/discourse/pull/42094"
},
{
"name": "https://github.com/discourse/discourse/commit/0248e9ca82d0493037a9ca04d73904ccfad795f9",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/discourse/discourse/commit/0248e9ca82d0493037a9ca04d73904ccfad795f9"
},
{
"name": "https://github.com/discourse/discourse/commit/03444ddb74d535dda557350f4c5800a6ec2669d7",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/discourse/discourse/commit/03444ddb74d535dda557350f4c5800a6ec2669d7"
},
{
"name": "https://github.com/discourse/discourse/commit/900f51c147913f667e64484c2f2dd48c723314ac",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/discourse/discourse/commit/900f51c147913f667e64484c2f2dd48c723314ac"
},
{
"name": "https://github.com/discourse/discourse/commit/da84c677213cac3b024e753f180f45472b89efde",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/discourse/discourse/commit/da84c677213cac3b024e753f180f45472b89efde"
}
],
"source": {
"advisory": "GHSA-4p6q-h74v-5j7p",
"discovery": "UNKNOWN"
},
"title": "Discourse: Anonymous sidebar serialization exposes descriptions of category-restricted tags"
}
},
"cveMetadata": {
"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"assignerShortName": "GitHub_M",
"cveId": "CVE-2026-72723",
"datePublished": "2026-08-10T15:56:53.723Z",
"dateReserved": "2026-08-10T13:48:09.545Z",
"dateUpdated": "2026-08-10T21:11:02.865Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-72723",
"date": "2026-09-17",
"epss": "0.00385",
"percentile": "0.32232"
},
"nvd": {
"cve": {
"affected": [
{
"affectedData": [
{
"product": "discourse",
"vendor": "discourse",
"versions": [
{
"status": "affected",
"version": "\u003c 2026.1.6"
},
{
"status": "affected",
"version": "\u003e= 2026.5.0-latest, \u003c 2026.5.2"
},
{
"status": "affected",
"version": "\u003e= 2026.6.0-latest, \u003c 2026.6.1"
},
{
"status": "affected",
"version": "\u003e= 2026.7.0-latest, \u003c 2026.7.0"
}
]
}
],
"source": "security-advisories@github.com"
}
],
"cveTags": [],
"descriptions": [
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"lang": "en",
"value": "Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, SiteSerializer.anonymous_default_navigation_menu_tags serializes tags from SiteSetting.default_navigation_menu_tags without applying DiscourseTagging.filter_visible for the anonymous viewer. An unauthenticated user can retrieve restricted tag names and descriptions through /site.json when those tags are limited by inaccessible categories, category tag groups, or tag-group permissions. This issue is fixed in versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0."
}
],
"id": "CVE-2026-72723",
"lastModified": "2026-09-08T20:54:37.790",
"metrics": {
"cvssMetricV31": [
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"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 5.3,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "LOW",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
"version": "3.1"
},
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"impactScore": 1.4,
"source": "security-advisories@github.com",
"type": "Secondary"
}
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"options": [
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},
{
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},
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"timestamp": "2026-08-10T19:02:43.987708Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-08-10T16:19:49.667",
"references": [
{
"source": "security-advisories@github.com",
"url": "https://github.com/discourse/discourse/commit/0248e9ca82d0493037a9ca04d73904ccfad795f9"
},
{
"source": "security-advisories@github.com",
"url": "https://github.com/discourse/discourse/commit/03444ddb74d535dda557350f4c5800a6ec2669d7"
},
{
"source": "security-advisories@github.com",
"url": "https://github.com/discourse/discourse/commit/900f51c147913f667e64484c2f2dd48c723314ac"
},
{
"source": "security-advisories@github.com",
"url": "https://github.com/discourse/discourse/commit/da84c677213cac3b024e753f180f45472b89efde"
},
{
"source": "security-advisories@github.com",
"url": "https://github.com/discourse/discourse/pull/42091"
},
{
"source": "security-advisories@github.com",
"url": "https://github.com/discourse/discourse/pull/42092"
},
{
"source": "security-advisories@github.com",
"url": "https://github.com/discourse/discourse/pull/42093"
},
{
"source": "security-advisories@github.com",
"url": "https://github.com/discourse/discourse/pull/42094"
},
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],
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"vulnStatus": "Deferred",
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"value": "CWE-862"
}
],
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"type": "Secondary"
}
]
}
},
"vulnrichment": {
"containers": {
"adp": [
{
"metrics": [
{
"other": {
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"id": "CVE-2026-72723",
"options": [
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},
{
"Technical Impact": "partial"
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],
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"timestamp": "2026-08-10T19:02:43.987708Z",
"version": "2.0.3"
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],
"providerMetadata": {
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"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
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],
"cna": {
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{
"product": "discourse",
"vendor": "discourse",
"versions": [
{
"status": "affected",
"version": "\u003c 2026.1.6"
},
{
"status": "affected",
"version": "\u003e= 2026.5.0-latest, \u003c 2026.5.2"
},
{
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},
{
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"version": "\u003e= 2026.7.0-latest, \u003c 2026.7.0"
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}
],
"descriptions": [
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"value": "Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, SiteSerializer.anonymous_default_navigation_menu_tags serializes tags from SiteSetting.default_navigation_menu_tags without applying DiscourseTagging.filter_visible for the anonymous viewer. An unauthenticated user can retrieve restricted tag names and descriptions through /site.json when those tags are limited by inaccessible categories, category tag groups, or tag-group permissions. This issue is fixed in versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 5.3,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "LOW",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
"version": "3.1"
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],
"problemTypes": [
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],
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},
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"tags": [
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},
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],
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},
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"tags": [
"x_refsource_MISC"
],
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},
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],
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},
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],
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},
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},
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}
],
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"discovery": "UNKNOWN"
},
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},
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"state": "PUBLISHED"
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}
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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.
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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.
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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.
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