CVE-2026-119206 is a vulnerability in pypdf that allows an attacker to craft a PDF file causing long runtimes when retrieving page labels. This can lead to performance degradation during PDF processing. The issue affects pypdf versions starting from 0.16.4. A fix is available in pypdf version 6.21.3. Users unable to upgrade immediately can apply the changes from pull request #4251 as a workaround.