Malicious code in runhelper (npm)

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.

--- _-= Per source details. Do not edit below this line.=-_ ## Source: amazon-inspector (3b30a78c30f51a72d8501b77d0cf6190319b8876ed7a119cc2f885adc3618212) On `require('runhelper')`, index.js unconditionally loads a payload file staged by its dependency `imgbundle` at `cdn-img-fetch/.runtime/rt.jpg`, allocates executable memory via kernel32 `VirtualAlloc` with `PAGE_EXECUTE_READWRITE` (0x40) and `MEM_COMMIT|MEM_RESERVE` (0x3000) through the `koffi` FFI, copies the file bytes with `RtlMoveMemory`, and executes them with `CreateThread`. The payload file is deleted after launch, and an `fs.watch` waits for it if not yet present. The `.jpg` extension in a hidden `.runtime` directory disguises an executable payload, and all errors are swallowed with empty `catch (_) {}` blocks. The advertised `exec()` spawn wrapper described in the README is a cover story: the module's top-level behavior on load is native shellcode execution. The manifest pins `imgbundle@^1.0.0` (payload source) and `koffi@^2.8.0` (FFI used to run it); the loader/payload split means anything that transitively requires runhelper on Windows fetches and executes attacker-supplied native code in-process.

Source published

30 Sep 2026 05:29:04 UTC

Source modified

30 Sep 2026 06:00:05 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.