CVE-2016-0998: Use-after-free vulnerability in Adobe Flash Player before 18.0.0.333 and 19.x through 21.x before 21.0.0.182 on Windows and OS X and before 11.2.202.577 on…

PriorityP270high8.8CVSS 3.1

AVNACLPRNUIRSUCHIHAH

EXPLOIT

EPSS

29.59%

98.0th percentile

Use-after-free vulnerability in Adobe Flash Player before 18.0.0.333 and 19.x through 21.x before 21.0.0.182 on Windows and OS X and before 11.2.202.577 on Linux, Adobe AIR before 21.0.0.176, Adobe AIR SDK before 21.0.0.176, and Adobe AIR SDK & Compiler before 21.0.0.176 allows attackers to execute arbitrary code via unspecified vectors, a different vulnerability than CVE-2016-0987, CVE-2016-0988, CVE-2016-0990, CVE-2016-0991, CVE-2016-0994, CVE-2016-0995, CVE-2016-0996, CVE-2016-0997, CVE-2016-0999, and CVE-2016-1000.

Affected

8 ranges

Vendor	Product	Version range	Fixed in
adobe	air	<= 20.0.0.233	—
adobe	air_desktop_runtime	<= 20.0.0.260	—
adobe	air_sdk	<= 20.0.0.260	—
adobe	air_sdk_compiler	<= 20.0.0.260	—
adobe	flash_player	<= 20.0.0.306	—
adobe	flash_player	<= 11.2.202.569	—
adobe	flash_player_desktop_runtime	<= 20.2.2.306	—
samsung	x14j_firmware	—	—

Detection & IOCsextracted from sources · hover to see the quote

urlhttps://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/39612.zip↗

urlhttps://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/39631.zip↗

filenamecrasher2.swf↗

→Detect ActionScript execution of Object.unwatch() with zero parameters — the vulnerability is triggered by calling o.unwatch() on an empty object with no arguments, causing alloca(0) and an uninitialized stack parameter access. ↗
→Monitor for SWF files loaded with query parameters manipulating stack layout (e.g., ?num=<0-31>), which is a technique used in the PoC to shift the stack and trigger crashes across different browsers. ↗
→The root cause is the unwatch() method calling toString on args[0] before checking that args_size >= 1; detection logic should flag Flash content invoking unwatch() on objects without parameters in ActionScript 2 contexts. ↗

·The vulnerability is specifically in the ActionScript 2 use-after-free fix introduced in the December 2015 Flash bulletin (APSB15-32); the uninitialized variable was introduced by Adobe's own patch, meaning patched-but-still-vulnerable versions exist between the December 2015 and March 2016 bulletins. ↗
·The PoC is described as 'finicky' and requires a specific two-step load sequence (crasher2.swf?num=15 followed immediately by crasher2.swf?num=4) to reliably trigger the crash; real-world exploitation reliability may vary by browser and stack state. ↗

CVSS provenance

nvdv3.18.8HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

nvdv2.09.3CRITICALAV:N/AC:M/Au:N/C:C/I:C/A:C

osv8.8HIGH

vendor_redhat8.8HIGH

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