Low-entropy hashing enables HashDoS
Published Nov 11, 2022 · Updated Apr 15, 2025
Insufficiently random values in Drogon 1.8.0 and 1.8.1 allow remote attackers to cause service interruption through crafted requests. The Session Hash Handler used deterministic std::unordered_map hashing for request headers, cookies, parameters, and response collections, letting attackers generate collisions and consume excessive CPU. Exploitation requires network access; the documented impact is limited to availability degradation, with no confidentiality or integrity impact reported.
Summary
What happened
Insufficiently random values in Drogon 1.8.0 and 1.8.1 allow remote attackers to cause service interruption through crafted requests. The Session Hash Handler used deterministic std::unordered_map hashing for request headers, cookies, parameters, and response collections, letting attackers generate collisions and consume excessive CPU. Exploitation requires network access; the documented impact is limited to availability degradation, with no confidentiality or integrity impact reported.
The record
- CVE
- CVE-2022-3959
- Published
- Nov 11, 2022
- Updated
- Apr 15, 2025
- Vendor
- Drogon
- Product
- Drogon
- Classifications
- CWE-330, T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Nov 11, 2022CVE publishedPublication date reported by the CVE source.
- Apr 15, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=1.8.0
- Affected versionversion=1.8.1
What conditions does exploitation require?
What is affected?
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
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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