Security Experts:

Flash Player Update Patches Disclosed Code Execution Flaw

Security updates released on Tuesday by Adobe for Flash Player address a critical vulnerability whose details were disclosed a few days earlier.

The security hole, tracked as CVE-2018-15981, has been described by Adobe as a type confusion bug that allows an attacker to execute arbitrary code in the context of the current user. The flaw has been assigned a priority rating of “1,” which means users should update as soon as possible due to the high risk of exploitation.

The vulnerability has been patched in Flash Player for Windows, macOS, Linux, and Chrome OS with the release of version 31.0.0.153. Version 31.0.0.148 and earlier are impacted.

Adobe warns that technical details about this weakness are publicly available. While the company’s advisory does not credit anyone for discovering the vulnerability, the software giant told SecurityWeek that the issue was identified by Israel-based researcher Gil Dabah.

Dabah wrote a post describing the vulnerability on his personal blog on November 13. A link to the post was published on Twitter the next day. It’s unclear why he decided to make his findings public before Adobe released a patch, but on November 15 he did praise the vendor “for touching base and working on a fix.”

“The interpreter code of the Action Script Virtual Machine (AVM) does not reset a with-scope pointer when an exception is caught, leading later to a type confusion bug, and eventually to a remote code execution,” Dabah explained in his blog post.

This is the second disclosed vulnerability patched by Adobe this month. The company’s Patch Tuesday updates for November 2018 include a fix for a flaw that can lead to hashed NTLM passwords getting leaked.

The security hole had been disclosed by Check Point in April and later patched by Adobe, but EdgeSpot recently discovered that the initial fix could be bypassed.

UPDATE. Dabah told SecurityWeek that this is not the first time he has dropped a Flash Player zero-day and will not be the last.

Related: Adobe Patches Vulnerabilities in Flash Player, ColdFusion

Related: Adobe Patches Flash Zero-Day Exploited in Targeted Attacks

Related: Over 100 Vulnerabilities Patched in Adobe Acrobat, Reader

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Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.