Hulumi: Drift classifier fails open on adapter errors and over-promotes Mixed verdicts

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Hulumi is an open-source toolkit that ships secure-by-default cloud and platform infrastructure components for Pulumi. Prior to version 1.4.0, consumers running drift detection in CI / cron could see transient adapter failures silently cached as "all clear" — masking real attacks for up to six hours — or see ordinary provider-version churn falsely promoted to incident severity. Either way, the verdict source was unreliable for downstream incident workflows that gate on it. This issue has been patched in version 1.4.0.

Source published

24 Jul 2026 18:44:05 UTC

Source modified

25 Jul 2026 00:58:23 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 4.0 · 8.4 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:H/SA:L

Hulumi is an open-source toolkit that ships secure-by-default cloud and platform infrastructure components for Pulumi. Prior to version 1.4.0, consumers running drift detection in CI / cron could see transient adapter failures silently cached as "all clear" — masking real attacks for up to six hours — or see ordinary provider-version churn falsely promoted to incident severity. Either way, the verdict source was unreliable for downstream incident workflows that gate on it. This issue has been patched in version 1.4.0.

Source published

24 Jul 2026 19:16:58 UTC

Source modified

24 Oct 2026 13:10:00 UTC

Observed here

25 Oct 2026 12:17:26 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · [email protected] · Secondary · 8.4 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:H/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

**Affected:** `@hulumi/drift` `< 1.4.0` — **Fixed in:** `1.4.0` — **Severity:** Medium — **CWE-755 (Improper Handling of Exceptional Conditions)** #### Summary `@hulumi/drift` runs four adapters that each ask a different question about whether a resource has drifted (Pulumi-state diff, provider-version change, CloudTrail event, etc.). A classifier combines the adapters' answers into a verdict like `None / none`, `ConsoleBreakGlass / high`, or `Mixed / high`, and caches the verdict for 6 hours by default. Two related bugs from one root cause — the classifier only read each adapter's `detected: true/false` field and ignored whether the adapter itself succeeded: 1. **Cached "all clear" on adapter failure.** When an adapter failed (e.g. transient network error from the Automation API), the classifier read `detected: false`, concluded "no drift", and cached the verdict as `None / none` for 6 hours. A single transient failure could mask real console-break-glass mutations for the rest of the window. 2. **Mixed verdicts without real evidence.** The `Mixed / high` and `ConsoleBreakGlass / high` verdicts (incident severity) could fire on the "the CloudTrail probe round-tripped successfully" signal rather than actual evidence that anything had been changed via the console. Normal provider-API churn could end up falsely escalated to incident severity. #### Impact Consumers running drift detection in CI / cron could see transient adapter failures silently cached as "all clear" — masking real attacks for up to six hours — or see ordinary provider-version churn falsely promoted to incident severity. Either way, the verdict source was unreliable for downstream incident workflows that gate on it. #### Patches Upgrade to `@hulumi/[email protected]`. Classifier-only fix (the TLA+-verified 6-row verdict matrix is byte-identical): - adapter failures now fail closed to `Unknown / low`, and degraded verdicts are not written to the cache; - the `Mixed` / `ConsoleBreakGlass` promotion now requires real CloudTrail event evidence rather than probe liveness. #### Workarounds Setting `options.minConfidence: "medium"` on the classifier call prevents the degraded `None / none` from being cached (it doesn't meet the threshold), partially mitigating case (1). No workaround for case (2). #### Resources - [PR #178](https://github.com/kerberosmansour/hulumi/pull/178) (Cluster D); regression tests in `packages/drift/tests/classifier-fail-closed.test.ts`.

Source published

10 Jun 2026 13:38:50 UTC

Source modified

10 Sep 2026 03:51:07 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:L/SC:N/SI:H/SA:L

Publisher rating · HIGH