Authorization bypass via URI fragment mishandling
Published Aug 24, 2021 · Updated Aug 3, 2024
Authorization bypass in Envoy allows remote attackers to reach protected upstream paths by placing a fragment in a crafted request URI. URI path handling retains or percent-encodes the fragment before path-based RBAC matching, so a protected final path element does not match its rule. Exploitation requires path-based authorization whose decision changes when the fragment is appended, and it can disclose resources behind that rule.
Summary
What happened
Authorization bypass in Envoy allows remote attackers to reach protected upstream paths by placing a fragment in a crafted request URI. URI path handling retains or percent-encodes the fragment before path-based RBAC matching, so a protected final path element does not match its rule. Exploitation requires path-based authorization whose decision changes when the fragment is appended, and it can disclose resources behind that rule.
The record
- CVE
- CVE-2021-32779
- Published
- Aug 24, 2021
- Updated
- Aug 3, 2024
- Vendor
- Envoy Proxy
- Product
- Envoy
- Classifications
- CWE-551, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 24, 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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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=>= 1.16.0, < 1.16.5
- Affected versionversion=>= 1.17.0, < 1.17.4
- Affected versionversion=>= 1.18.0, < 1.18.4
- Affected versionversion=>= 1.19.0, < 1.19.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
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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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