GNOME Dia up to 0.98+git20260221-1 WPG parser wpg-import.c fread heap-based overflow

Summaryinfo

A vulnerability classified as problematic has been found in GNOME Dia up to 0.98+git20260221-1. Impacted is the function fread of the file plug-ins/wpg/wpg-import.c of the component WPG parser. Performing a manipulation results in heap-based overflow. This vulnerability is identified as CVE-2026-77652. The attack is only possible with local access. There is not any exploit available.

Detailsinfo

A vulnerability was found in GNOME Dia up to 0.98+git20260221-1. It has been classified as problematic. This affects the function fread of the file plug-ins/wpg/wpg-import.c of the component WPG parser. The manipulation with an unknown input leads to a heap-based overflow vulnerability. CWE is classifying the issue as CWE-122. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

A heap-based buffer overflow vulnerability exists in the Dia diagram editor WPG file format importer. In plug-ins/wpg/wpg-import.c, the WPG import renderer allocates a fixed palette with: ren->pPal = g_new0(WPGColorRGB, 256); When handling a WPG_COLORMAP record, the parser reads a start index (i16) and number of colors (iNum16) from the file and reads palette data with: bRet &= (iNum16 == (int)fread(&ren->pPal[i16], sizeof(WPGColorRGB), iNum16, f)); The only bounds-related check is `if (i16 >= 0 && i16 <= iSize)`, where iSize is the WPG record size—not the palette capacity. There is no validation that i16 is less than 256 or that i16 + iNum16 does not exceed 256. A malicious WPG file can supply i16=256 and iNum16=264. That causes fread() to write 792 bytes starting at &pPal[256], while the palette buffer is only 768 bytes (256 entries × 3 bytes). This overflows into adjacent heap metadata and can crash Dia (SIGABRT / malloc corruption errors) or, depending on heap layout and exploit primitives, potentially lead to arbitrary code execution. Exploitation requires convincing a user to open a crafted WPG file via Dia's file dialog, command line, or file association. No special privileges are required to deliver the file to the victim. Affected component: WPG parser (plug-ins/wpg/wpg-import.c). Affected versions: all Dia versions containing this code path (reporter tested Dia 0.98+git20260221-1; issue present on upstream master as of 2026-08-21).

The advisory is shared at access.redhat.com. This vulnerability is uniquely identified as CVE-2026-77652 since 08/21/2026. The exploitability is told to be easy. An attack has to be approached locally. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 08/26/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

• GNOME

Name

• Dia

Version

• 0.98+git20260221-1

License

• open-source

Website

• Vendor: https://www.gnome.org/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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