Denial of service via unbounded auth state
Published Sep 4, 2026 · Updated Sep 4, 2026
Denial of service in SiYuan before 3.8.2 allows remote attackers to degrade availability through repeated Basic Auth failures. The publish-service throttle indexes failed-attempt state by remote address and attacker-controlled username but never bounds or independently evicts unrelated keys. A network-reachable publish service with Basic Auth enabled is sufficient; unique invalid usernames retain memory and add synchronization overhead without valid credentials.
Summary
What happened
Denial of service in SiYuan before 3.8.2 allows remote attackers to degrade availability through repeated Basic Auth failures. The publish-service throttle indexes failed-attempt state by remote address and attacker-controlled username but never bounds or independently evicts unrelated keys. A network-reachable publish service with Basic Auth enabled is sufficient; unique invalid usernames retain memory and add synchronization overhead without valid credentials.
The record
- CVE
- CVE-2026-85584
- Published
- Sep 4, 2026
- Updated
- Sep 4, 2026
- Vendor
- SiYuan Note
- Product
- SiYuan
- Classifications
- T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 4, 2026CVE publishedPublication date reported by the CVE source.
- Sep 4, 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=0 <3.8.2
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
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
- Bounded unique-username Basic Auth loopproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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