CVE-2026-55420 (GCVE-0-2026-55420)
Vulnerability from cvelistv5 – Published: 2026-07-09 17:54 – Updated: 2026-07-14 01:08
VLAI
EPSS
VEX
Title
Discourse: Remote code execution via pdf uploads
Summary
Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, under certain non-default configurations, processing of PDF uploads could be exploited to obtain RCE on the server. This issue is patched in 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5.
Severity
7.5 (High)
SSVC
Exploitation: none
Automatable: no
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-07-14 01:08 UTC
CWE
- CWE-78 - Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
Assigner
References
6 references
| URL | Tags |
|---|---|
| https://github.com/discourse/discourse/security/a… | x_refsource_CONFIRM |
| https://github.com/discourse/discourse/commit/ca5… | x_refsource_MISC |
| https://github.com/discourse/discourse/releases/t… | x_refsource_MISC |
| https://github.com/discourse/discourse/releases/t… | x_refsource_MISC |
| https://github.com/discourse/discourse/releases/t… | x_refsource_MISC |
| https://github.com/discourse/discourse/releases/t… | x_refsource_MISC |
Impacted products
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{
"name": "https://github.com/discourse/discourse/commit/ca5a7e06167561928556afa2f237d67e459c6914",
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"url": "https://github.com/discourse/discourse/commit/ca5a7e06167561928556afa2f237d67e459c6914"
},
{
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},
{
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"tags": [
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"url": "https://github.com/discourse/discourse/releases/tag/v2026.5.1"
},
{
"name": "https://github.com/discourse/discourse/releases/tag/v2026.6.0",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/discourse/discourse/releases/tag/v2026.6.0"
}
],
"source": {
"advisory": "GHSA-7wq5-jgww-5rw3",
"discovery": "UNKNOWN"
},
"title": "Discourse: Remote code execution via pdf uploads"
}
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"cveMetadata": {
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}
],
"id": "CVE-2026-55420",
"lastModified": "2026-07-14T02:16:56.050",
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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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