{"id":"DEBIAN-CVE-2026-77658","details":"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-\u003enum_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","modified":"2026-09-14T17:03:34.237913103Z","published":"2026-08-26T13:19:22.043Z","upstream":["CVE-2026-77658"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-77658"}],"affected":[{"package":{"name":"dia","ecosystem":"Debian:12","purl":"pkg:deb/debian/dia?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.97.3+git20220525-5","0.98+git20240130-1","0.98+git20240528-1","0.98+git20240814-1","0.98+git20250126-1","0.98+git20250126-2","0.98+git20250827-1","0.98+git20250827-2","0.98+git20260221-1","0.98+git20260221-2","0.98+git20260221-3"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-77658.json"}},{"package":{"name":"dia","ecosystem":"Debian:13","purl":"pkg:deb/debian/dia?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.98+git20250126-2","0.98+git20250827-1","0.98+git20250827-2","0.98+git20260221-1","0.98+git20260221-2","0.98+git20260221-3"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-77658.json"}},{"package":{"name":"dia","ecosystem":"Debian:14","purl":"pkg:deb/debian/dia?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.98+git20250126-2","0.98+git20250827-1","0.98+git20250827-2","0.98+git20260221-1","0.98+git20260221-2","0.98+git20260221-3"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-77658.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"}]}