DeepDiff versions from 5.0.0 up to (but not including) 8.6.2 contain a flaw in the pickle unpickler where classes allowed in SAFE_TO_IMPORT can be instantiated with constructor arguments that allocate memory proportional to input data. A crafted 40‑byte pickle payload can force more than ten gigabytes of memory allocation, causing the process to crash and resulting in a denial of service. The vulnerability directly leads to memory exhaustion and application unavailability, impacting system stability and uptime.

The affected product is DeepDiff by seperman. Versions 5.0.0 through 8.6.1 are impacted. The issue was fixed in version 8.6.2, so any deployment using an earlier release remains vulnerable.

The CVSS score of 8.7 indicates high severity, yet the EPSS score is under 1%, suggesting a low probability of exploitation at present. The vulnerability is not listed in CISA KEV. The likely attack vector is the processing of untrusted pickle data—such as files or data received over a network—by applications that invoke DeepDiff. Successful exploitation would cause a temporary or permanent service outage due to excessive memory usage.