Adobe has patched a zero-day vulnerability in its PDF software that hackers have been exploiting since at least November 2025, with the exact number of compromised individuals remaining unknown. The bug, which was used in targeted attacks, allowed hackers to gain unauthorized access to sensitive information. This type of exploit is particularly concerning as it occurs before a patch is available, leaving defenders at a disadvantage1. The fact that the vulnerability was exploited for months underscores the need for prompt action in addressing such security flaws. The patch, released by Adobe, aims to mitigate the issue, but the damage may already be done. So what matters to practitioners is that this incident highlights the importance of proactive security measures, such as regularly updating software and monitoring for suspicious activity, to stay ahead of potential threats.