IBM HTTP Server 8.5 and 9.0 contain an optional module, mod_ibm_upload, that can be compromised to cause a server process crash. The vulnerability originates from improper handling of input within this module; when exploited a legitimate process terminates, leading to unavailable web services and potential repeated downtime. The weakness aligns with CWE‑476, which denotes a null pointer dereference that can be triggered by unexpected input.

IBM HTTP Server 8.5.x (versions 8.5.0.0 through 8.5.5.29) and 9.0.x (versions 9.0.0.0 through 9.0.5.28) that include the optional mod_ibm_upload module are affected. The vulnerability applies to installations that have not applied the interim fix PH71265 or the subsequent fix packs 8.5.5.30+ for 8.5 series and 9.0.5.29+ for 9.0 series.

The CVSS score of 7.5 indicates a high severity for this denial of service issue. EPSS data is not available, so the probability of exploitation cannot be quantified. The vulnerability is not listed in the CISA KEV catalogue. Based on the description, it is inferred that the exploit is triggered through an HTTP request directed at the optional module, meaning remote network access to the affected port is required. An attacker capable of sending such requests could repeatedly crash the server, leading to significant availability disruption until the patch is applied.