{"answers":{"affected":"1 open source package ship an affected version, including checkout-signer.","exploited":"There is no known exploitation of MAL-2026-5436 in the wild and no public exploit code.","fix":"Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.","what":"MAL-2026-5436 is a malicious package in checkout-signer, published on 9 Jun 2026."},"fix_prompt":"MAL-2026-5436 is a malicious package: checkout-signer (npm). Every version was published to cause harm.\n\nTask:\n1. Search this repository's dependency manifests and lockfiles for the package, including transitive dependencies.\n2. If it is present, remove it, regenerate the lockfile with the project's package manager, and replace whatever it was used for.\n3. List any CI runners, developer machines or containers that installed it, so their secrets can be rotated.\n4. If the package is not used anywhere, say so and change nothing.\n\nReference: https://insights.sbomify.com/MAL-2026-5436/ (Markdown: https://insights.sbomify.com/MAL-2026-5436/index.md)","id":"MAL-2026-5436","markdown":"https://insights.sbomify.com/MAL-2026-5436/index.md","name":"MAL-2026-5436","record":{"aliases":[],"analysis":null,"analysis_generated_by":null,"assigner":null,"cpe":[],"cvss":{"score":null,"severity":null,"source":null,"vector":null,"version":null},"cwes":[],"description":"Package replicates the API surface of an internal Exodus package (`generateMnemonicSigningKeys`, `signDirectPaymentMultiChain`, `signCapture`, `signRefund`, `signCharge`, `signCancelSubscription` exported from `src/index.js`), where each export throws an error rather than implementing the real signing logic. On `npm install`, `src/canary.js` (line 6) performs a DNS lookup and HTTPS GET to a hardcoded serveo.net tunnel host (`https://96e03fa6c292469a-172-245-86-254.serveousercontent.com/canary-install`), sending the package name and version. Any organization that pulls this from the public registry believing it to be the internal Exodus dependency reveals their install (org / CI host identification via DNS + HTTPS source) to the operator of the tunnel. README claims the package performs only a DNS lookup with no data transmission, contradicting the actual HTTPS GET with query parameters. The beacon destination is a mutable serveo tunnel pointing at a residential-style IP (172.245.86.254), which is operator-controllable infrastructure rather than a stable vendor endpoint. Regardless of any stated 'authorized research' framing, the structure — divergent-API namespace-abuse shape plus an unconsented install-time beacon to a tunneling host — is the live dependency-confusion attack pattern.","ecosystems":["npm"],"exploits":{"exploitdb":null,"first_seen":null,"github_poc":null,"max_poc_stars":null,"metasploit":null,"nuclei":null,"refs":[],"tier":null},"has_fix":false,"headline":"Malicious code in checkout-signer (npm)","id":"MAL-2026-5436","indexable":true,"kev":null,"kind":"malicious","links":{"ecosystem":"npm","product":null,"products":[],"type":null,"year":"2026"},"n_packages":1,"n_references":null,"packages":[{"ecosystem":"npm","fixed":[],"introduced":[],"last_affected":[],"package":"checkout-signer","purl":"pkg:npm/checkout-signer","source":"MAL-2026-5436"}],"products":null,"published":"2026-06-09","related":[],"sources":[{"class":"attribution","licence":"Apache-2.0","name":"OpenSSF Malicious Packages","prefix":"MAL"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":null,"updated":null,"vendors":null},"summary":null,"url":"https://insights.sbomify.com/MAL-2026-5436/"}