Azure AD token theft via plaintext cache storage
Published Jun 26, 2026 · Updated Jun 26, 2026
Cleartext token storage in OpenProject before 17.3.3 and 17.4.0 allows attackers with cache read access to steal an Azure AD bearer token. The Storages module writes the OneDrive/SharePoint userless OAuth access_token in plaintext to Rails.cache under the deterministic storage..httpx_access_token key, and hourly jobs and OAuth calls continually repopulate it. Exploitation requires read access to the file_store, memcache, or Redis backend; the recovered application-tier bearer permits access within its Azure AD authorization scope.
Summary
What happened
Cleartext token storage in OpenProject before 17.3.3 and 17.4.0 allows attackers with cache read access to steal an Azure AD bearer token. The Storages module writes the OneDrive/SharePoint userless OAuth access_token in plaintext to Rails.cache under the deterministic storage..httpx_access_token key, and hourly jobs and OAuth calls continually repopulate it. Exploitation requires read access to the file_store, memcache, or Redis backend; the recovered application-tier bearer permits access within its Azure AD authorization scope.
The record
- CVE
- CVE-2026-52783
- Published
- Jun 26, 2026
- Updated
- Jun 26, 2026
- Vendor
- OpenProject GmbH
- Product
- OpenProject
- Classifications
- CWE-313, T1552.001
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 26, 2026CVE publishedPublication date reported by the CVE source.
- Jun 26, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 17.3.3
- Affected versionversion=>= 17.4.0, < 17.4.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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