F´: FileDownlink SendPartial integer overflow lets legal startOffset/length values reach a reachable assertion

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.

F´ (F Prime) is a framework that enables development and deployment of spaceflight and other embedded software applications. Prior to 4.3.0, Svc::FileDownlink SendPartial range validation is vulnerable because unchecked startOffset plus length arithmetic bypasses the range check and stores a wrapped m_endOffset that is inconsistent with m_byteOffset. When an existing source file is larger than a valid startOffset and a SendPartial command supplies a length whose U32 sum with that offset wraps below the file size, under standard F Prime assertion handling, the first data-packet transition reaches FW_ASSERT and aborts or resets the process, causing denial of service. This issue is fixed in version 4.3.0.

Source published

14 Oct 2026 17:09:20 UTC

Source modified

20 Oct 2026 01:42:27 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

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CVSS 3.1 · 6.5 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H