CVE-2026-72720 (GCVE-0-2026-72720)
Vulnerability from cvelistv5 – Published: 2026-08-10 15:41 – Updated: 2026-08-10 18:17
VLAI
EPSS
VEX
Title
Discourse: HTML injection in PrettyText.format_for_email from cooked-attribute reparsing
Summary
Discourse is an open-source discussion platform. Prior to 2026.1.7, 2026.6.2, 2026.7.1, and 2026.8.0-latest.1, Discourse has HTML injection in PrettyText.format_for_email because cooked attribute values are reparsed as markup. Crafted Vimeo iframe sources, secure-upload URLs or dimensions, and hashtag data-slug values can cause decoded attribute text to be reinterpreted as HTML. The vulnerable conversion also fails to strictly validate the Vimeo iframe host and path, allowing non-Vimeo allowlisted iframes to be converted. This issue is fixed in versions 2026.1.7, 2026.6.2, 2026.7.1, and 2026.8.0-latest.1.
Severity
6.4 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-10 18:13 UTC
CWE
- CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Assigner
References
9 references
| URL | Tags |
|---|---|
| https://github.com/discourse/discourse/security/a… | x_refsource_CONFIRM |
| https://github.com/discourse/discourse/pull/42244 | x_refsource_MISC |
| https://github.com/discourse/discourse/pull/42245 | x_refsource_MISC |
| https://github.com/discourse/discourse/pull/42246 | x_refsource_MISC |
| https://github.com/discourse/discourse/pull/42247 | x_refsource_MISC |
| https://github.com/discourse/discourse/commit/234… | x_refsource_MISC |
| https://github.com/discourse/discourse/commit/4b6… | x_refsource_MISC |
| https://github.com/discourse/discourse/commit/a5d… | x_refsource_MISC |
| https://github.com/discourse/discourse/commit/b25… | x_refsource_MISC |
Impacted products
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"tags": [
"x_refsource_MISC"
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"url": "https://github.com/discourse/discourse/pull/42247"
},
{
"name": "https://github.com/discourse/discourse/commit/234ee88a5b9b53bf938c53351eab20130323485f",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/discourse/discourse/commit/234ee88a5b9b53bf938c53351eab20130323485f"
},
{
"name": "https://github.com/discourse/discourse/commit/4b639a52f47fb3d46093bece9df147e4e9517a11",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/discourse/discourse/commit/4b639a52f47fb3d46093bece9df147e4e9517a11"
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{
"name": "https://github.com/discourse/discourse/commit/a5d3b112d598242c1d1803d5a77bf98d5fdabd75",
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"x_refsource_MISC"
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"url": "https://github.com/discourse/discourse/commit/a5d3b112d598242c1d1803d5a77bf98d5fdabd75"
},
{
"name": "https://github.com/discourse/discourse/commit/b25a074b165253e01fc4c8911b980fc68338ea16",
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"x_refsource_MISC"
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"url": "https://github.com/discourse/discourse/commit/b25a074b165253e01fc4c8911b980fc68338ea16"
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"discovery": "UNKNOWN"
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"title": "Discourse: HTML injection in PrettyText.format_for_email from cooked-attribute reparsing"
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"cveId": "CVE-2026-72720",
"datePublished": "2026-08-10T15:41:51.764Z",
"dateReserved": "2026-08-10T13:48:09.545Z",
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{
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}
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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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