Denial of service via unlimited HTTP headers
Published Sep 13, 2026 · Updated Sep 13, 2026
Improper HTTP request handling in UnrealIRCd 6.0.5 through 6.2.6 allows remote attackers to hang the server via excessive headers. The built-in webserver accepts and retains an unbounded number of request headers, consuming memory until the daemon becomes unresponsive. The issue is reachable only when a WebSocket or JSON-RPC listener is enabled, a configuration that is disabled by default; successful exploitation interrupts IRC service.
Summary
What happened
Improper HTTP request handling in UnrealIRCd 6.0.5 through 6.2.6 allows remote attackers to hang the server via excessive headers. The built-in webserver accepts and retains an unbounded number of request headers, consuming memory until the daemon becomes unresponsive. The issue is reachable only when a WebSocket or JSON-RPC listener is enabled, a configuration that is disabled by default; successful exploitation interrupts IRC service.
The record
- CVE
- CVE-2026-90668
- Published
- Sep 13, 2026
- Updated
- Sep 13, 2026
- Vendor
- UnrealIRCd
- Product
- UnrealIRCd
- Classifications
- T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 13, 2026CVE publishedPublication date reported by the CVE source.
- Sep 13, 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=6.0.5 <6.2.7
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
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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