An attacker who uses this vulnerability can craft a PDF which leads to the RAM being exhausted. This requires accessing an image using /FlateDecode with large size values.
This has been fixed in pypdf==6.10.2.
If you cannot upgrade yet, consider applying the changes from PR #3734.
6.10.2Exploitability
AV:LAC:LAT:NPR:NUI:PVulnerable System
VC:NVI:NVA:HSubsequent System
SC:NSI:NSA:N6.8/CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N