CVSS v3
7.5
HIGH
EPSS Score
0.6 %
exploit probability, as of 2026-09-28
CISA KEV
No
known exploited
Exploitation
—
SSVC status
Description
The webserver in UnrealIRCd 6.0.5 through 6.2.6 before 6.2.7 does not limit the number of HTTP request headers, which allows remote attackers to cause a denial of service (memory consumption and unresponsive server) via an HTTP request with an unlimited number of headers, if a websocket or JSON-RPC listener is enabled (disabled by default).
Technical details
- Published
- 2026-09-13
- Last Modified
- 2026-09-13
Frequently asked questions
What is CVE-2026-90668?
The webserver in UnrealIRCd 6.0.5 through 6.2.6 before 6.2.7 does not limit the number of HTTP request headers, which allows remote attackers to cause a denial of service (memory consumption and unresponsive server) via an HTTP request with an unlimited number of headers, if a websocket or JSON-RPC listener is enabled (disabled by default).
Is CVE-2026-90668 actively exploited?
Active exploitation of CVE-2026-90668 has not been confirmed. Its EPSS score was 0.6% on 2026-09-28, the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2026-90668?
CVE-2026-90668 has a CVSS v3 base score of 7.5 (HIGH severity).
Is CVE-2026-90668 affecting your environment?
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