{"id":"CVE-2026-76288","kind":"vulnerability","aliases":["CVE-2026-76288"],"related":[],"title":"Splunk Enterprise: one crafted request takes Splunk Web offline","description":"In Splunk Enterprise versions below 10.4.4, 10.2.8, 10.0.11, and 9.4.16, an unauthenticated user could send a single crafted request to the Splunk Web JavaScript logger endpoint and cause Splunk Web to stop responding to requests. Splunk Web remains unavailable until Splunk Enterprise is restarted.\nThe vulnerability is possible because Splunk Web does not limit request-header parsing before processing the request.","summary":"An unauthenticated attacker can send a single crafted request to the Splunk Web JavaScript logger endpoint, which stops Splunk Web from answering requests. Splunk Web stays down until Splunk Enterprise is restarted, because request-header parsing has no size limit.","severity":"high","cvss":7.5,"epss":0.00372,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["infrastructure","self-hosted","splunk","web-ui"],"not_affected_if":["managed-hosting","splunk-web-disabled"],"how_to_check":"- Check the installed Splunk Enterprise version with `$SPLUNK_HOME/bin/splunk version` and compare it with the fixed releases below.\n- Check whether Splunk Web is exposed to untrusted networks, for example on port `8000` from the internet.","fix":"- Upgrade Splunk Enterprise to `10.4.4`, `10.2.8`, `10.0.11`, or `9.4.16`, matching your release line.\n- Until you can upgrade, restrict access to Splunk Web to trusted networks.","status":"open","published_at":"2026-10-21T23:17:26+00:00","first_seen_at":"2026-10-23T21:57:29+00:00","triaged_at":"2026-10-25T03:16:22+00:00","updated_at":"2026-10-25T03:16:22+00:00","category":"infrastructure","confidence":0.8,"triage":{"at":"2026-10-25T03:16:22Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade Splunk Enterprise to `10.4.4`, `10.2.8`, `10.0.11`, or `9.4.16`, matching your release line.\n- Until you can upgrade, restrict access to Splunk Web to trusted networks.","reach":"network","title":"Splunk Enterprise: one crafted request takes Splunk Web offline","impact":"low","summary":"An unauthenticated attacker can send a single crafted request to the Splunk Web JavaScript logger endpoint, which stops Splunk Web from answering requests. Splunk Web stays down until Splunk Enterprise is restarted, because request-header parsing has no size limit.","category":"infrastructure","nicknames":[],"who_cares":["splunk","self-hosted","web-ui"],"confidence":0.8,"needs_auth":"no","worst_case":"Splunk Web stops responding until the service is restarted","analyst_note":"","how_to_check":"- Check the installed Splunk Enterprise version with `$SPLUNK_HOME/bin/splunk version` and compare it with the fixed releases below.\n- Check whether Splunk Web is exposed to untrusted networks, for example on port `8000` from the internet.","needs_analyst":false,"not_affected_if":["managed-hosting","splunk-web-disabled"],"who_is_affected":"Any Splunk Enterprise deployment below the fixed versions that serves Splunk Web is exposed, and an unauthenticated request is enough to trigger the outage. Splunk Cloud, Universal Forwarders and deployments with Splunk Web disabled are not described as affected by the sources.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.00064,"input_tokens":3429,"output_tokens":594,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-2026':11A,14A '-76288':12A,15A '10.0.11':72C '10.2.8':71C '10.4.4':70C '9.4.16':74C 'answer':45B 'attack':26B 'caus':92C 'could':78C 'craft':4A,31B,82C 'cve':10A,13A 'endpoint':39B,90C 'enterpris':2A,53B,67C,106C 'header':59B,121C 'host':19B 'infrastructur':16B 'javascript':37B,88C 'limit':64B,118C 'logger':38B,89C 'offlin':9A 'one':3A 'pars':60B,122C 'possibl':112C 'process':124C 'remain':102C 'request':5A,32B,46B,58B,83C,99C,120C,126C 'request-head':57B,119C 'respond':97C 'restart':55B,108C 'self':18B 'self-host':17B 'send':28B,79C 'singl':30B,81C 'size':63B 'splunk':1A,7A,20B,35B,42B,47B,52B,66C,86C,93C,100C,105C,114C 'stay':49B 'stop':41B,96C 'take':6A 'ui':23B 'unauthent':25B,76C 'unavail':103C 'user':77C 'version':68C 'vulner':110C 'web':8A,22B,36B,43B,48B,87C,94C,101C,115C 'web-ui':21B","nicknames":[],"mitigations":[],"who_affected":"Any Splunk Enterprise deployment below the fixed versions that serves Splunk Web is exposed, and an unauthenticated request is enough to trigger the outage. Splunk Cloud, Universal Forwarders and deployments with Splunk Web disabled are not described as affected by the sources.","tier":"B","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-21T23:17:26+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cvss_by":"psirt@cisco.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-76288","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-76288","severity":null,"published_at":"2026-10-21T23:17:26+00:00","modified_at":"2026-10-22T16:57:10+00:00","first_seen_at":"2026-10-23T21:57:29+00:00","fetched_at":"2026-10-23T22:29:02+00:00","note":null},{"source":"epss","external_id":"CVE-2026-76288","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-76288","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-24T13:15:54+00:00","fetched_at":"2026-10-24T13:15:54+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}