{"id":"CVE-2026-20253","published":"2026-06-10T18:16:40Z","modified":"2026-07-23T09:10:00Z","title":"Splunk Enterprise Missing Authentication for Critical Function Vulnerability","vendor":"Splunk","product":"Enterprise","tier":"core","eol":null,"description":{"text":"In Splunk Enterprise 10.2 versions below 10.2.4 and 10 versions below 10.0.7, an unauthenticated user could create or truncate arbitrary files through a PostgreSQL sidecar service endpoint. The vulnerability exists because the PostgreSQL sidecar service endpoint lacks authentication controls, allowing any network-reachable user to invoke file operations without credentials. Splunk Enterprise versions 9.4 and earlier are not affected. If you cannot immediately upgrade to a fixed version, you can mitigate this vulnerability by disabling the PostgreSQL sidecar service.","provenance":"source","from":"NVD"},"summary":{"text":"Splunk Enterprise (versions 10.2 below 10.2.4 and 10.0 below 10.0.7) has a missing authentication flaw in its PostgreSQL sidecar service endpoint, which lacks access controls on file operations. An attacker with network access to that endpoint can create or truncate arbitrary files without any credentials, requiring no user interaction or special configuration.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-29T08:31:54Z"},"cvss":{"score":9.8,"severity":"CRITICAL","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","provenance":"source","from":"NVD"},"epss":{"score":0.96939,"percentile":0.99888,"date":"2026-10-30","provenance":"source"},"kev":{"dateAdded":"2026-06-18","dueDate":"2026-06-21","ransomware":false,"requiredAction":"Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.","notes":"https://advisory.splunk.com/advisories/SVD-2026-0603 ; BOD 26-04: https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk ; Forensics Triage Requirements: https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk ; https://nvd.nist.gov/vuln/detail/CVE-2026-20253","provenance":"source"},"vulncheckKev":{"dateAdded":"2026-06-15","exploitedFirstSeen":"2026-06-15","ransomware":false,"evidence":[{"url":"https://previdian.com/CVE-2026-20253","date":"2026-06-15"},{"url":"https://advisory.splunk.com/advisories/SVD-2026-0603","date":"2026-06-18"},{"url":"https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json","date":"2026-06-18"},{"url":"https://www.crowdsec.net/vulntracking-report/cve-2026-20253-splunk-authentication-bypass","date":"2026-06-22"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2026-07-09&host_type=src&vulnerability=cve-2026-20253","date":"2026-07-09"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2026-07-10&host_type=src&vulnerability=cve-2026-20253","date":"2026-07-10"},{"url":"https://www.recordedfuture.com/blog/june-2026-cve-landscape","date":"2026-07-10"},{"url":"https://hunt.io/blog/open-directory-nginx-rift-ghost-cms-multi-cve","date":"2026-07-20"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2026-08-05&host_type=src&vulnerability=cve-2026-20253","date":"2026-08-05"},{"url":"https://dashboard.shadowserver.org/statistics/honeypot/vulnerability/map/?day=2026-08-06&host_type=src&vulnerability=cve-2026-20253","date":"2026-08-06"}],"evidenceTotal":63,"provenance":"source"},"exploited":true,"otx":{"pulseCount":50,"pulses":[{"name":"Actively_Exploited_Kev | Oct 31, 2026","url":"https://otx.alienvault.com/pulse/6ae4aefab0c2191cecd41862","created":"2026-10-30"},{"name":"Actively_Exploited_Kev | Oct 30, 2026","url":"https://otx.alienvault.com/pulse/6ae35d889ea92b4ce19c2680","created":"2026-10-29"},{"name":"CVE-2026-88771: Inside the Exploitation of a Critical NetScaler RCE Vulnerability","url":"https://otx.alienvault.com/pulse/6ae28386158c5f73da5c681b","created":"2026-10-28"},{"name":"Node2Shell / HTTP2Shell Vulnerability May Allow RCE","url":"https://otx.alienvault.com/pulse/6ae280ad7e93493f1842dcc5","created":"2026-10-28"},{"name":"Node2Shell / HTTP2Shell Vulnerability May Allow RCE","url":"https://otx.alienvault.com/pulse/6ae2424aa801637ecf4942df","created":"2026-10-28"},{"name":"Actively_Exploited_Kev | Oct 29, 2026","url":"https://otx.alienvault.com/pulse/6ae20c1db17e7057ae7d9ad1","created":"2026-10-28"},{"name":"Actively_Exploited_Kev | Oct 28, 2026","url":"https://otx.alienvault.com/pulse/6ae0ba7e0e2a97ff7b218819","created":"2026-10-27"},{"name":"Actively_Exploited_Kev | Oct 27, 2026","url":"https://otx.alienvault.com/pulse/6adf68b85c3e852f3c111d18","created":"2026-10-26"},{"name":"Actively_Exploited_Kev | Oct 24, 2026","url":"https://otx.alienvault.com/pulse/6adb740e397c3ad4799aa4cd","created":"2026-10-23"},{"name":"Actively_Exploited_Kev | Oct 23, 2026","url":"https://otx.alienvault.com/pulse/6ada236fcfba2dfa730ea482","created":"2026-10-22"}],"provenance":"machine"},"cwes":[{"id":"CWE-306","name":"Missing Authentication for Critical Functionality"}],"references":[{"url":"https://advisory.splunk.com/advisories/SVD-2026-0603","tags":["Mitigation","Vendor Advisory"]},{"url":"https://labs.watchtowr.com/why-use-app-level-auth-when-every-database-has-auth-splunk-enterprise-cve-2026-20253-pre-auth-rce/","tags":["Exploit","Third Party Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-20253","tags":["US Government Resource"]}],"techniques":[{"id":"T1190","name":"Exploit Public-Facing Application","tactics":["initial-access"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: unauthenticated network endpoint exposed to attackers","mappingType":"exploitation_technique","evidence":[{"from":"description","quote":"an unauthenticated user could create or truncate arbitrary files through a PostgreSQL sidecar service endpoint","start":78,"end":188}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"},{"id":"T1565.001","name":"Stored Data Manipulation","tactics":["impact"],"provenance":"ai","basis":"ai-mapping","bases":["ai-mapping"],"basisDetail":"claude-haiku-5-5: file creation/truncation alters stored data","mappingType":"primary_impact","evidence":[{"from":"description","quote":"could create or truncate arbitrary files","start":102,"end":142}],"model":"claude-haiku-5-5","confidence":"medium","confidenceNote":"AI-mapped from the description (quote-validated, not expert-reviewed)"}],"reports":[],"affected":[],"advisories":[],"euvd":{"id":"EUVD-2026-36088","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-36088","exploited":true,"exploitedSince":"2026-06-18","provenance":"source"},"exploits":[],"exploitSources":{"pocGithub":{"count":5,"skipped":2,"earliest":"2026-06-12","earliestUrl":"https://github.com/watchtowrlabs/watchTowr-vs-Splunk-CVE-2026-20253","repos":[{"name":"watchtowrlabs/watchTowr-vs-Splunk-CVE-2026-20253","url":"https://github.com/watchtowrlabs/watchTowr-vs-Splunk-CVE-2026-20253","stars":13,"created":"2026-06-12"},{"name":"0xBlackash/CVE-2026-20253","url":"https://github.com/0xBlackash/CVE-2026-20253","stars":5,"created":"2026-06-13"},{"name":"HORKimhab/CVE-2026-20253","url":"https://github.com/HORKimhab/CVE-2026-20253","stars":0,"created":"2026-06-14"},{"name":"fevar54/CVE-2026-20253-Splunk-Enterprise-Pre-Auth-RCE-","url":"https://github.com/fevar54/CVE-2026-20253-Splunk-Enterprise-Pre-Auth-RCE-","stars":0,"created":"2026-06-26"},{"name":"pssec-io/CVE-2026-20253","url":"https://github.com/pssec-io/CVE-2026-20253","stars":0,"created":"2026-06-29"}]},"nuclei":[{"id":"CVE-2026-20253","name":"Splunk 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PoC-in-GitHub","url":"https://github.com/watchtowrlabs/watchTowr-vs-Splunk-CVE-2026-20253","provenance":"source"},{"date":"2026-06-15","kind":"exploited-reported","label":"Exploitation first reported (VulnCheck KEV evidence)","url":"https://previdian.com/CVE-2026-20253","provenance":"source"},{"date":"2026-06-18","kind":"kev","label":"Added to CISA KEV","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","provenance":"source"},{"date":"2026-06-18","kind":"euvd-exploited","label":"ENISA EUVD: exploited","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-36088","provenance":"source"}],"speed":{"daysToPublicExploit":2,"firstExploitFrom":"PoC-in-GitHub","daysToKev":8},"priority":{"score":74.8,"factors":[{"name":"In a KEV catalog","points":35.0,"detail":"listed in CISA KEV and VulnCheck KEV"},{"name":"Recent KEV listing","points":5.0,"detail":"added 138 days ago"},{"name":"Known ransomware use","points":0.0,"detail":"not known"},{"name":"EPSS percentile","points":19.98,"detail":"percentile 0.9989"},{"name":"Named in threat reports","points":0.0,"detail":"0 reports"},{"name":"Public exploit code","points":5.0,"detail":"1 NVD reference tagged Exploit; 5 PoC-in-GitHub repos; 1 nuclei template"},{"name":"Mentioned in OTX pulses","points":3.0,"detail":"50 pulses"},{"name":"CVSS severity","points":6.86,"detail":"base score 9.8"},{"name":"End-of-life product","points":0.0,"detail":"supported or unknown"}]}}