{"id":"CVE-2026-48034","aliases":["GHSA-9vc9-4jv3-rf86"],"title":"@hulumi/policies has a HULUMI-H5 bypass via decoy sibling resources targeting a different bucket","summary":"@hulumi/policies has a HULUMI-H5 bypass via decoy sibling resources targeting a different bucket","severity":"high","cwe":["CWE-284"],"vendor":"hulumi","product":"@hulumi/policies","ecosystem":"npm","affected":["@hulumi/policies < 1.4.0"],"patched":["@hulumi/policies 1.4.0"],"published":"2026-06-10","updated":"2026-06-10","source":"GHSA","sourceUrl":"https://github.com/advisories/GHSA-9vc9-4jv3-rf86","references":[{"url":"https://github.com/kerberosmansour/hulumi/security/advisories/GHSA-9vc9-4jv3-rf86"},{"url":"https://github.com/kerberosmansour/hulumi/pull/175"},{"url":"https://github.com/kerberosmansour/hulumi/pull/178"},{"url":"https://github.com/advisories/GHSA-9vc9-4jv3-rf86"}],"tags":["ghsa","npm"],"ingestedAt":"2026-07-07T15:41:59.577Z","epss":0.00258,"epssPercentile":0.17835,"slug":"CVE-2026-48034","body":"## Overview\n\n**Affected:** `@hulumi/policies` `< 1.4.0` — **Fixed in:** `1.4.0` — **Severity:** High — **CWE-284 (Improper Access Control)**\n\n#### Summary\n\nHULUMI-H1 forbids raw `aws:s3:Bucket` outside of Hulumi's `SecureBucket` component, with one exemption: a raw bucket that's a child of a `SecureBucket` is allowed because the component is responsible for the hardening. HULUMI-H5 is the defence-in-depth check that closes the H1 exemption — for any raw bucket claiming it, H5 verifies the five hardening sibling resources a real `SecureBucket` always emits (public-access block, SSE-KMS, ownership controls, versioning, TLS-only bucket policy) are actually present.\n\nThe bug: H5 only checked the siblings' _types_. It never verified that those siblings actually applied to the bucket being exempted. A consumer (or compromised PR) could pair an unhardened raw bucket with five hardening sibling resources whose `bucket` property pointed at a _completely different_ bucket, and H5 would report no violation while the actual bucket shipped with zero hardened defaults.\n\n#### Impact\n\nConsumers using `HulumiHardeningPack` could ship a raw S3 bucket with no public-access block, no SSE-KMS, no ownership controls, no versioning, and no TLS-only bucket policy — while the policy pack reported the stack as compliant.\n\n#### Patches\n\nUpgrade to `@hulumi/policies@1.4.0`. The H5 sibling check now requires both (a) the sibling to share the same parent `SecureBucket` instance via the anchored URN helper from GHSA-2, AND (b) the sibling's `bucket` property — or, for the bucket policy, its `Resource` ARN list — to reference the exempted bucket explicitly. Five decoy siblings pointing at a different bucket no longer count.\n\n#### Workarounds\n\nNone — the exemption itself is the mechanism, so the value-binding check is the only fix.\n\n#### Resources\n\n- [PR #178](https://github.com/kerberosmansour/hulumi/pull/178) (Cluster B); decoy-sibling regression cases in `packages/policies/tests/hulumi-hardening-pack.test.ts`. Supersedes [PR #175](https://github.com/kerberosmansour/hulumi/pull/175), which had addressed the value-binding half but on a stale base.\n\n## Affected packages\n\n- `@hulumi/policies < 1.4.0`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `@hulumi/policies 1.4.0`","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}