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Vulnerability record · CVE-2026-90668 · published 13 September 2026

CVE-2026-90668: Allocation without limits vulnerability

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).

8.7 CVSS 4.0 High EPSS 0.58% · top 54.4% CWE-770 · Allocation without limits Deferred
8.7CVSS 4.0 base score
0.58%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
2References
22 Sep 2026Last modified by NVD

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).

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:

References

LinkTags
https://forums.unrealircd.org/viewtopic.php?t=9483
https://www.unrealircd.org/

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Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-90668), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.