This indicates an attack attempt to exploit a Denial of Service vulnerability against Apache HTTP Web Server.
The vulnerability is due to the application failing to adequately sanitize HTTP header strings. A remote attack may be able to exploit this to cause a denial of service condition on the affected system via a malformed HTTP header.
Apache Software Foundation Apache 2.0.47 - 2.0.49
Denial of Service: Remote attackers can crash vulnerable systems.
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