GUIX JPEG Decoder Buffer Overread via SOF0 After SOS
CVE-2026-91059 Published on October 20, 2026
JPEG decoder: a duplicate SOF0 after SOS publishes a pixelmap that misreports its own allocation size
The GUIX JPEG software decoder enforces no ordering on JPEG markers. A file that places a second `SOF0` frame header after `SOS` re-runs the frame header parser after the output buffer has already been allocated and its geometry latched. The decoder returns `GX_SUCCESS` and publishes a `GX_PIXELMAP` whose reported dimensions and `data_size` exceed the allocation behind it.
Any consumer that trusts the returned structure reads out of bounds, including GUIX's own display drivers, reached through the ordinary draw path.
Reproduces in the shipped default configuration; `GX_SOFTWARE_DECODER_SUPPORT` is enabled by default.
Vulnerability Analysis
CVE-2026-91059 can be exploited with local system access. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity and availability.
Weakness Type
Out-of-bounds Read
The software reads data past the end, or before the beginning, of the intended buffer. Typically, this can allow attackers to read sensitive information from other memory locations or cause a crash. A crash can occur when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string. The expected sentinel might not be located in the out-of-bounds memory, causing excessive data to be read, leading to a segmentation fault or a buffer overflow. The software may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent read operation then produces undefined or unexpected results.
Products Associated with CVE-2026-91059
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Affected Versions
Eclipse Foundation Eclipse ThreadX - GUIX:- Before and including 6.5.1.202602a is affected.
- Version 6.5.2.202603 is unaffected.