{"id":"CVE-2026-54316","state":"PUBLISHED","title":"Claude Code: Out-of-Band Data Exfiltration via Pre-Approved HuggingFace Domain in WebFetch","description":"Claude Code is an agentic coding tool.  From 0.2.54 until 2.1.163, because the hostname huggingface.co was pre-approved as a bare hostname for the WebFetch tool, any path on that domain—including attacker-controlled model repositories—was auto-approved without a permission prompt or being subject to --allowedTools restrictions. An attacker able to inject untrusted content into a Claude Code context could direct it to issue WebFetch requests against attacker-controlled repository files (e.g. /resolve/main/config.json), which HuggingFace counts as downloads server-side, creating a covert out-of-band channel for encoding and exfiltrating data Claude can access such as files, environment variables, or command output. Reliably exploiting this required the ability to add untrusted content into a Claude Code context window. This vulnerability is fixed in 2.1.163.","publishedAt":"2026-06-23T17:06:16.184Z","updatedAt":"2026-06-23T17:37:38.468Z","severity":{"score":6,"label":"Medium","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["anthropics claude-code"],"affected":[{"vendor":"anthropics","product":"claude-code","versions":[{"version":">= 0.2.54, < 2.1.163","status":"affected"}]}],"references":["https://github.com/anthropics/claude-code/security/advisories/GHSA-fg94-h982-f3mm"],"weaknesses":["CWE-183","CWE-200","CWE-515"],"ingestedAt":"2026-10-29T20:12:24.861Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/54xxx/CVE-2026-54316.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-54316","state":"PUBLISHED","datePublished":"2026-06-23T17:06:16.184Z","dateUpdated":"2026-06-23T17:37:38.468Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-12T18:42:02.223Z"},"containers":{"cna":{"title":"Claude Code: Out-of-Band Data Exfiltration via Pre-Approved HuggingFace Domain in WebFetch","descriptions":[{"lang":"en","value":"Claude Code is an agentic coding tool.  From 0.2.54 until 2.1.163, because the hostname huggingface.co was pre-approved as a bare hostname for the WebFetch tool, any path on that domain—including attacker-controlled model repositories—was auto-approved without a permission prompt or being subject to --allowedTools restrictions. An attacker able to inject untrusted content into a Claude Code context could direct it to issue WebFetch requests against attacker-controlled repository files (e.g. /resolve/main/config.json), which HuggingFace counts as downloads server-side, creating a covert out-of-band channel for encoding and exfiltrating data Claude can access such as files, environment variables, or command output. Reliably exploiting this required the ability to add untrusted content into a Claude Code context window. This vulnerability is fixed in 2.1.163."}],"affected":[{"vendor":"anthropics","product":"claude-code","versions":[{"version":">= 0.2.54, < 2.1.163","status":"affected"}]}],"references":[{"url":"https://github.com/anthropics/claude-code/security/advisories/GHSA-fg94-h982-f3mm","name":"https://github.com/anthropics/claude-code/security/advisories/GHSA-fg94-h982-f3mm","tags":["x_refsource_CONFIRM"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"PASSIVE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":6,"baseSeverity":"MEDIUM","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-183","lang":"en","description":"CWE-183: Permissive List of Allowed Inputs","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-200","lang":"en","description":"CWE-200: Exposure of Sensitive Information to an Unauthorized Actor","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-515","lang":"en","description":"CWE-515: Covert Storage Channel","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-06-23T17:06:16.184Z"},"source":{"advisory":"GHSA-fg94-h982-f3mm","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-06-23T17:37:32.464559Z","id":"CVE-2026-54316","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-06-23T17:37:38.468Z"}}]}}}