A heap-based buffer overflow issue was discovered in libjpeg-turbo in h2v2_merged_upsample_internal() function of jdmrgext.c file. The vulnerability can only be exploited with 12-bit data precision for which the range of the sample data type exceeds the valid sample range, hence, an attacker could craft a 12-bit lossless JPEG image that contains out-of-range 12-bit samples. An application attempting to decompress such image using merged upsampling would lead to segmentation fault or buffer overflows, causing an application to crash.
Severity
CVSS 3.1
6.5 medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
EPSS
1.2% chance of exploitation in the next 30 days; higher than 68% of CVEs (scores of 2026-10-31)