CVE-2021-40729: 
Adobe Acrobat Reader Continuous vulnerability analysis and mitigation

Adobe Acrobat Reader DC versions 21.007.20095 (and earlier), 21.007.20096 (and earlier), 20.004.30015 (and earlier), and 17.011.30202 (and earlier) were affected by an out-of-bounds read vulnerability identified as CVE-2021-40729. The vulnerability was discovered by Kai Lu of Zscaler's ThreatLabz and was publicly disclosed on September 8, 2021 (CVE Mitre, Adobe Security).

The vulnerability is characterized as an out-of-bounds read issue that could potentially expose sensitive memory information. The CVSS score for this vulnerability indicates a medium severity level with a vector string of (AV:N/AC:M/Au:N/C:P/I:N/A:N) (Rapid7).

If successfully exploited, this vulnerability could lead to the disclosure of sensitive memory information and potentially allow attackers to bypass security mitigations such as ASLR (Address Space Layout Randomization). The exploitation requires user interaction, specifically opening a malicious PDF file (CVE Mitre).

Adobe addressed this vulnerability through security updates released in their security bulletin APSB21-104. Users are advised to update to the latest version of Adobe Acrobat Reader DC to mitigate this vulnerability (Adobe Security).