{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-27977","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-02-25T03:24:57.793Z","datePublished":"2026-03-17T23:56:24.631Z","dateUpdated":"2026-03-18T19:56:16.843Z"},"containers":{"cna":{"title":"Next.js: null origin can bypass dev HMR websocket CSRF checks","problemTypes":[{"descriptions":[{"cweId":"CWE-1385","lang":"en","description":"CWE-1385: Missing Origin Validation in WebSockets","type":"CWE"}]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"PASSIVE","vulnConfidentialityImpact":"LOW","vulnIntegrityImpact":"LOW","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":2.3,"baseSeverity":"LOW","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N","version":"4.0"}}],"references":[{"name":"https://github.com/vercel/next.js/security/advisories/GHSA-jcc7-9wpm-mj36","tags":["x_refsource_CONFIRM"],"url":"https://github.com/vercel/next.js/security/advisories/GHSA-jcc7-9wpm-mj36"},{"name":"https://github.com/vercel/next.js/commit/862f9b9bb41d235e0d8cf44aa811e7fd118cee2a","tags":["x_refsource_MISC"],"url":"https://github.com/vercel/next.js/commit/862f9b9bb41d235e0d8cf44aa811e7fd118cee2a"},{"name":"https://github.com/vercel/next.js/releases/tag/v16.1.7","tags":["x_refsource_MISC"],"url":"https://github.com/vercel/next.js/releases/tag/v16.1.7"}],"affected":[{"vendor":"vercel","product":"next.js","versions":[{"version":">= 16.0.1, < 16.1.7","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-03-18T00:23:47.523Z"},"descriptions":[{"lang":"en","value":"Next.js is a React framework for building full-stack web applications. Starting in version 16.0.1 and prior to version 16.1.7, in `next dev`, cross-site protection for internal websocket endpoints could treat `Origin: null` as a bypass case even if `allowedDevOrigins` is configured, allowing privacy-sensitive/opaque contexts (for example sandboxed documents) to connect unexpectedly. If a dev server is reachable from attacker-controlled content, an attacker may be able to connect to the HMR websocket channel and interact with dev websocket traffic. This affects development mode only. Apps without a configured `allowedDevOrigins` still allow connections from any origin. The issue is fixed in version 16.1.7 by validating `Origin: null` through the same cross-site origin-allowance checks used for other origins. If upgrading is not immediately possible, do not expose `next dev` to untrusted networks and/or block websocket upgrades to `/_next/webpack-hmr` when `Origin` is `null` at the proxy."}],"source":{"advisory":"GHSA-jcc7-9wpm-mj36","discovery":"UNKNOWN"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-03-18T19:56:08.547586Z","id":"CVE-2026-27977","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-03-18T19:56:16.843Z"}}]}}