File-type restriction bypass via unchecked attachment renaming
Published Apr 28, 2021 · Updated Aug 3, 2024
Attachment validation in Redmine before 4.0.9, 4.1.x before 4.1.3, and 4.2.x before 4.2.1 allows remote attackers to bypass extension restrictions. The attachment workflow checks the original filename during upload but accepts a replacement filename when attaching or later editing the file without revalidating its extension. When an extension allowlist is configured, any role permitted to add or rename attachments can store content under a forbidden extension.
Summary
What happened
Attachment validation in Redmine before 4.0.9, 4.1.x before 4.1.3, and 4.2.x before 4.2.1 allows remote attackers to bypass extension restrictions. The attachment workflow checks the original filename during upload but accepts a replacement filename when attaching or later editing the file without revalidating its extension. When an extension allowlist is configured, any role permitted to add or rename attachments can store content under a forbidden extension.
The record
- CVE
- CVE-2021-31865
- Published
- Apr 28, 2021
- Updated
- Aug 3, 2024
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- Unavailable
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 28, 2021CVE publishedPublication date reported by the CVE source.
- Aug 3, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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What is affected?
Affected products and versions are unavailable in this record.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
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Public exploit references
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Technologies
Your stack
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Your stack
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