{"id":"CVE-2026-20256","state":"PUBLISHED","title":"Improper Input Validation through Protocol-Relative URL in Classic Dashboards in Splunk Enterprise","description":"In Splunk Enterprise versions below 10.2.4, 10.0.7, 9.4.12, and 9.3.13, and Splunk Cloud Platform versions below 10.3.2512.13, 10.2.2510.15, 10.1.2507.23, and 9.3.2411.132, a low-privileged user that does not hold the 'admin' or 'power' Splunk roles could cause data exfiltration through classic dashboards by redirecting a victim to an external site using a protocol-relative URL in a drill-down link.<br><br>The vulnerability exists because the URL classifier in classic dashboards only recognizes `http://` and `https://` schemes when checking for external URLs. Protocol-relative URLs such as `//attacker.com` bypass this check entirely, and Splunk Web does not show the external-navigation warning dialog to the victim.","publishedAt":"2026-06-10T17:15:55.966Z","updatedAt":"2026-06-10T18:19:26.044Z","severity":{"score":5.7,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N","source":"cisco"},"assigner":"cisco","products":["Splunk Splunk Enterprise","Splunk Splunk Cloud Platform"],"affected":[{"vendor":"Splunk","product":"Splunk Enterprise","versions":[{"version":"10.2","status":"affected","lessThan":"10.2.4","versionType":"custom"},{"version":"10.0","status":"affected","lessThan":"10.0.7","versionType":"custom"},{"version":"9.4","status":"affected","lessThan":"9.4.12","versionType":"custom"},{"version":"9.3","status":"affected","lessThan":"9.3.13","versionType":"custom"}]},{"vendor":"Splunk","product":"Splunk Cloud Platform","versions":[{"version":"10.3.2512","status":"affected","lessThan":"10.3.2512.13","versionType":"custom"},{"version":"10.2.2510","status":"affected","lessThan":"10.2.2510.15","versionType":"custom"},{"version":"10.1.2507","status":"affected","lessThan":"10.1.2507.23","versionType":"custom"},{"version":"9.3.2411","status":"affected","lessThan":"9.3.2411.132","versionType":"custom"}]}],"references":["https://advisory.splunk.com/advisories/SVD-2026-0606"],"weaknesses":["CWE-20"],"ingestedAt":"2026-10-29T20:11:10.572Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/20xxx/CVE-2026-20256.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-20256","state":"PUBLISHED","datePublished":"2026-06-10T17:15:55.966Z","dateUpdated":"2026-06-10T18:19:26.044Z","assignerShortName":"cisco","assignerOrgId":"d1c1063e-7a18-46af-9102-31f8928bc633","dateReserved":"2025-10-08T11:59:15.401Z"},"containers":{"cna":{"title":"Improper Input Validation through Protocol-Relative URL in Classic Dashboards in Splunk Enterprise","descriptions":[{"lang":"en","value":"In Splunk Enterprise versions below 10.2.4, 10.0.7, 9.4.12, and 9.3.13, and Splunk Cloud Platform versions below 10.3.2512.13, 10.2.2510.15, 10.1.2507.23, and 9.3.2411.132, a low-privileged user that does not hold the 'admin' or 'power' Splunk roles could cause data exfiltration through classic dashboards by redirecting a victim to an external site using a protocol-relative URL in a drill-down link.<br><br>The vulnerability exists because the URL classifier in classic dashboards only recognizes `http://` and `https://` schemes when checking for external URLs. Protocol-relative URLs such as `//attacker.com` bypass this check entirely, and Splunk Web does not show the external-navigation warning dialog to the victim."}],"affected":[{"vendor":"Splunk","product":"Splunk Enterprise","versions":[{"version":"10.2","status":"affected","lessThan":"10.2.4","versionType":"custom"},{"version":"10.0","status":"affected","lessThan":"10.0.7","versionType":"custom"},{"version":"9.4","status":"affected","lessThan":"9.4.12","versionType":"custom"},{"version":"9.3","status":"affected","lessThan":"9.3.13","versionType":"custom"}]},{"vendor":"Splunk","product":"Splunk Cloud Platform","versions":[{"version":"10.3.2512","status":"affected","lessThan":"10.3.2512.13","versionType":"custom"},{"version":"10.2.2510","status":"affected","lessThan":"10.2.2510.15","versionType":"custom"},{"version":"10.1.2507","status":"affected","lessThan":"10.1.2507.23","versionType":"custom"},{"version":"9.3.2411","status":"affected","lessThan":"9.3.2411.132","versionType":"custom"}]}],"references":[{"url":"https://advisory.splunk.com/advisories/SVD-2026-0606"}],"metrics":[{"cvssV3_1":{"vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N","version":"3.1","baseScore":5.7,"baseSeverity":"MEDIUM"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-20","lang":"en","type":"cwe","description":"The product does not validate or incorrectly validates input that can affect the control flow or data flow of a program."}]}],"providerMetadata":{"shortName":"cisco","orgId":"d1c1063e-7a18-46af-9102-31f8928bc633","dateUpdated":"2026-06-10T17:15:55.966Z"},"datePublic":"2026-06-10T00:00:00.000Z","source":{"advisory":"SVD-2026-0606"},"credits":[{"lang":"en","value":"Tony Tong (tongster)"}]},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-06-10T18:18:59.939227Z","id":"CVE-2026-20256","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":"2026-06-10T18:19:26.044Z"}}]}}}