World-accessible IPC shared memory with predictable name in TightVNC Server

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

Incorrect permission assignment in GlavSoft TightVNC Server for Windows before 2.8.88 allows a local authenticated user to read or overwrite the inter-process communication handles used between the TightVNC service and its desktop server process. The named shared memory segment in the Global\ namespace that carries the pipe HANDLE values is created with a NULL DACL, and its name is derived from a time-seeded srand(time(0)) value that is predictable to one-second granularity. A low-privileged local process can open the mapping and tamper with the IPC channel of a service running as SYSTEM, potentially leading to disclosure of session data, privilege escalation, or denial of service.

Source published

8 Oct 2026 13:39:55 UTC

Source modified

8 Oct 2026 14:02:27 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

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CVSS 3.1 · 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H