CVE-2026-91057 in ThreadX
Summary
by MITRE • 10/20/2026
`_gx_multi_line_text_view_display_info_get()` reads one byte past the end of the application's text buffer when the string it is given ends with a carriage return (`\r`). The over-read can also cause callers to advance their index past the end of the string, producing a second over-read in `_gx_multi_line_text_view_string_total_rows_compute()` and a row of text that is not in the source.
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Analysis
by VulDB Data Team • 10/20/2026
The vulnerability identified within the GUIX library involves an out-of-bounds read condition located specifically in the function _gx_multi_line_text_view_display_info_get(). This flaw arises when processing string inputs that conclude with a carriage return character, denoted as \r. The underlying technical mechanism fails to properly account for the length of the input buffer relative to its termination conditions, leading the application to access memory locations immediately following the allocated text buffer boundary. This behavior constitutes an off-by-one error where the pointer arithmetic exceeds the valid data range by a single byte, resulting in the reading of uninitialized or unrelated heap memory contents.
The operational impact extends beyond this initial over-read due to cascading effects within related functions that depend on the output of _gx_multi_line_text_view_display_info_get(). Specifically, the function _gx_multi_line_text_string_total_rows_compute() utilizes data derived from the previous call and incorrectly advances its internal index past the actual end of the string. This secondary out-of-bounds read further exacerbates memory safety violations by accessing invalid memory regions during row calculation logic. Consequently, this can lead to unpredictable application behavior, including rendering artifacts where non-existent rows of text are displayed or processed, potentially causing visual corruption in graphical user interfaces that rely on accurate line counting and display metrics.
From a security perspective, this vulnerability aligns with CWE-125, which describes out-of-bounds read conditions. Such flaws can be exploited to leak sensitive information stored adjacent to the buffer in memory if an attacker can control or influence the content of the text input. Furthermore, depending on how the retrieved data is utilized downstream, it may contribute to logic errors that could facilitate more severe attacks such as denial of service through application crashes or instability. In terms of threat modeling and attack patterns, this behavior corresponds to ATT&CK technique T1082, which involves system information discovery via memory access, although in this context the primary risk is stability rather than intentional reconnaissance unless exploited deliberately by a malicious actor providing crafted input strings.
Mitigation strategies should focus on rigorous bounds checking within the GUIX library source code. Developers must ensure that all buffer read operations verify that indices do not exceed the allocated size of the text buffer, particularly when handling special characters like carriage returns that may affect string parsing logic. Implementing static analysis tools configured to detect off-by-one errors and out-of-bounds reads during the development phase is recommended. Additionally, fuzz testing with inputs containing various control characters can help identify similar edge cases in other parts of the library. Updating to patched versions of the GUIX framework where these boundary checks have been corrected by the vendor remains the most effective remediation path for deployed applications relying on this functionality.