An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires parsing the content stream of a page which has an inline image using the DCTDecode filter.
This has been fixed in pypdf==6.1.3.
If you cannot upgrade yet, consider applying the changes from PR #3501.
6.1.3Exploitability
AV:NAC:LAT:NPR:NUI:NVulnerable System
VC:NVI:NVA:HSubsequent System
SC:NSI:NSA:N6.6/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:U