F´: FpySequencer Integer Overflow in Stack Offset/Size Validation Leading to Out-of-Bounds Write

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 4.2.0, Svc::FpySequencer STORE directive stack write validation the bounds check adds attacker-controlled offset and size before memcpy, allowing integer wraparound to make an out-of-range destination appear valid. When a sequence-controlled STORE directive supplies a stack offset and size whose U32 sum wraps, memcpy can write outside the sequencer stack, causing memory corruption, denial of service, and potentially code execution. This issue is fixed in version 4.2.0.

Source published

14 Oct 2026 17:14:17 UTC

Source modified

29 Oct 2026 13:54:17 UTC

Observed here

29 Oct 2026 15:12:12 UTC

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CVSS 3.1 · 7.2 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H