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CVE-2026-77658— Dia: dia: stack buffer overflow in bus object via unvalidated handle count in project files

Quick assessment

Affected
GNOME Dia
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

在 Dia 图形编辑器处理来自 Dia XML 项目文件的“总线”（Network Bus）对象时，存在一个基于栈的缓冲区溢出漏洞。 在文件 中， 函数使用 从文件属性 读取总线句柄的数量，但未对其上限进行验证： 随后，当移动总线句柄时， 函数会在栈上分配两个临时数组： 由于 的值完全由攻击者通过项目文件控制，当该值足够大（例如 262144 或更高）时， 将消耗超出默认线程栈限制（在 Linux 上通常为 8 MB）的栈空间，从而导致栈溢出、SIGSEGV 信号错误，并可能引发栈帧或返回地址损坏。 攻击者可以在恶

CVSS 7.8 · High

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application
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I. Basic Information for CVE-2026-77658

Vulnerability Information
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Vulnerability Title
Dia: dia: stack buffer overflow in bus object via unvalidated handle count in project files
Source: CVE Program / CVE List V5
Vulnerability Description
A stack-based buffer overflow vulnerability exists in the Dia diagram editor when processing Network Bus objects from Dia XML project files. In objects/network/bus.c, bus_load() reads the number of bus handles from the file attribute "bus_handles" using attribute_num_data() without validating an upper bound: bus->num_handles = attribute_num_data(attr); When a bus handle is subsequently moved, bus_handle_moved() allocates two temporary arrays on the stack: parallel = (real *)g_alloca(num_handles * sizeof(real)); perp = (real *)g_alloca(num_handles * sizeof(real)); Because num_handles is fully attacker-controlled via the project file, sufficiently large values (for example 262144 or higher) cause g_alloca() to consume more stack space than the default thread stack limit (typically 8 MB on Linux), resulting in stack overflow, SIGSEGV, and potential stack frame / return-address corruption. An attacker can embed a Bus object with an excessive bus_handles count in a malicious .dia file. Exploitation requires the victim to open the file in Dia (file dialog, command line, or file association) and trigger handle manipulation (moving a bus handle), which exercises the vulnerable code path. The identical g_alloca pattern is present in objects/Misc/tree.c (copied from bus.c) and is likely vulnerable to the same class of attack via Tree objects. Affected versions: Dia 0.98.0 and earlier versions containing this code; issue confirmed on upstream master as of 2026-08-21. Upstream report: https://gitlab.gnome.org/GNOME/dia/-/issues/581
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
栈缓冲区溢出
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
GNOME Dia 0 ~ 0.98.0 -

II. Public POCs for CVE-2026-77658

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III. Intelligence Information for CVE-2026-77658

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Vendor Advisories for CVE-2026-77658 (1)

Vendor Pages for CVE-2026-77658 (1)

Other References for CVE-2026-77658 (1)

Other References for CVE-2026-77658 (1)

IV. Related Vulnerabilities

Same product: Dia
Same vendor: GNOME
Same weakness: CWE-121

V. Comments for CVE-2026-77658

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