{"id":"CVE-2020-1938","kind":"vulnerability","aliases":["CVE-2020-1938"],"related":[],"title":"Apache Tomcat: Apache Tomcat Improper Privilege Management Vulnerability","description":"When using the Apache JServ Protocol (AJP), care must be taken when trusting incoming connections to Apache Tomcat. Tomcat treats AJP connections as having higher trust than, for example, a similar HTTP connection. If such connections are available to an attacker, they can be exploited in ways that may be surprising. In Apache Tomcat 9.0.0.M1 to 9.0.0.30, 8.5.0 to 8.5.50 and 7.0.0 to 7.0.99, Tomcat shipped with an AJP Connector enabled by default that listened on all configured IP addresses. It was expected (and recommended in the security guide) that this Connector would be disabled if not required. This vulnerability report identified a mechanism that allowed: - returning arbitrary files from anywhere in the web application - processing any file in the web application as a JSP Further, if the web application allowed file upload and stored those files within the web application (or the attacker was able to control the content of the web application by some other means) then this, along with the ability to process a file as a JSP, made remote code execution possible. It is important to note that mitigation is only required if an AJP port is accessible to untrusted users. Users wishing to take a defence-in-depth approach and block the vector that permits returning arbitrary files and execution as JSP may upgrade to Apache Tomcat 9.0.31, 8.5.51 or 7.0.100 or later. A number of changes were made to the default AJP Connector configuration in 9.0.31 to harden the default configuration. It is likely that users upgrading to 9.0.31, 8.5.51 or 7.0.100 or later will need to make small changes to their configurations.","summary":"Apache Tomcat trusts AJP connections more than HTTP connections, so an attacker who can reach an AJP port can act with that elevated trust. This is the Ghostcat flaw, and CISA lists it as actively exploited.","severity":"critical","cvss":9.8,"epss":0.9927,"exploited":true,"exploited_at":"2022-03-03T00:00:00+00:00","products":[{"name":"Apache Tomcat","fixed":[],"affected":"","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["exploited","java","runtime","self-hosted","tomcat"],"not_affected_if":["ajp-connector-disabled","ajp-not-reachable-from-untrusted-networks"],"how_to_check":"Check whether the AJP connector is enabled in conf/server.xml (look for a Connector on port 8009 with protocol AJP).\nCheck whether port 8009 is reachable from untrusted networks.","fix":"Upgrade Apache Tomcat to a fixed release per vendor instructions (fixed versions not listed in sources).\nIf AJP is not needed, comment out the AJP Connector in server.xml; if needed, set an AJP secret or bind it to localhost only.","status":"open","published_at":"2020-02-24T22:15:12+00:00","first_seen_at":"2026-10-23T19:11:52+00:00","triaged_at":"2026-10-23T21:24:29+00:00","updated_at":"2026-10-23T21:57:35+00:00","category":"runtime","confidence":0.8,"triage":{"at":"2026-10-23T21:24:29Z","model":"claude-haiku-5-5","output":{"fix":"Upgrade Apache Tomcat to a fixed release per vendor instructions (fixed versions not listed in sources).\nIf AJP is not needed, comment out the AJP Connector in server.xml; if needed, set an AJP secret or bind it to localhost only.","reach":"network","impact":"high","summary":"Apache Tomcat trusts AJP connections more than HTTP connections, so an attacker who can reach an AJP port can act with that elevated trust. This is the Ghostcat flaw, and CISA lists it as actively exploited.","category":"runtime","who_cares":["tomcat","java","self-hosted"],"confidence":0.8,"needs_auth":"no","worst_case":"Attacker reads or changes web application files and may execute code on the server","analyst_note":"Confirm fixed Tomcat versions per branch from the Apache Tomcat security advisory for CVE-2020-1938 and the CISA KEV entry.","how_to_check":"Check whether the AJP connector is enabled in conf/server.xml (look for a Connector on port 8009 with protocol AJP).\nCheck whether port 8009 is reachable from untrusted networks.\nunknown","needs_analyst":true,"not_affected_if":["ajp-connector-disabled","ajp-not-reachable-from-untrusted-networks"],"user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"critical"},"cost_usd":0.000529,"input_tokens":2846,"output_tokens":489,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-1938':11A,14A '-2020':10A,13A '7.0.0':122C '7.0.100':287C,319C '7.0.99':124C '8.5.0':118C '8.5.50':120C '8.5.51':285C,317C '9.0.0':114C '9.0.0.30':117C '9.0.31':284C,303C,316C 'abil':224C 'abl':206C 'access':252C 'act':43B 'activ':58B 'address':140C 'ajp':27B,40B,66C,80C,129C,249C,299C 'allow':166C,191C 'along':221C 'anywher':171C 'apach':1A,3A,24B,63C,76C,112C,282C 'apache':15A 'applic':175C,182C,190C,201C,214C 'approach':265C 'arbitrari':168C,273C 'attack':35B,100C,204C 'avail':97C 'block':267C 'care':67C 'chang':293C,327C 'cisa':54B 'code':234C 'configur':138C,301C,308C,330C 'connect':28B,32B,74C,81C,92C,95C 'connector':130C,152C,300C 'content':210C 'control':208C 'cve':9A,12A 'default':133C,298C,307C 'defenc':262C 'defence-in-depth':261C 'depth':264C 'disabl':155C 'elev':46B 'enabl':131C 'exampl':88C 'execut':235C,276C 'expect':143C 'exploit':17B,59B,104C 'file':169C,178C,192C,197C,228C,274C 'flaw':52B 'ghostcat':51B 'guid':149C 'harden':305C 'higher':84C 'host':22B 'http':31B,91C 'identifi':162C 'import':239C 'improp':5A 'incom':73C 'ip':139C 'java':18B 'jserv':64C 'jsp':185C,231C,278C 'later':289C,321C 'like':311C 'list':55B 'listen':135C 'm1':115C 'made':232C,295C 'make':325C 'manag':7A 'may':108C,279C 'mean':218C 'mechan':164C 'mitig':243C 'must':68C 'need':323C 'note':241C 'number':291C 'permit':271C 'port':41B,250C 'possibl':236C 'privileg':6A 'process':176C,226C 'protocol':65C 'reach':38B 'recommend':145C 'remot':233C 'report':161C 'requir':158C,246C 'return':167C,272C 'runtim':19B 'secur':148C 'self':21B 'self-host':20B 'ship':126C 'similar':90C 'small':326C 'store':195C 'surpris':110C 'take':259C 'taken':70C 'tomcat':2A,4A,16A,23B,25B,77C,78C,113C,125C,283C 'treat':79C 'trust':26B,47B,72C,85C 'untrust':254C 'upgrad':280C,314C 'upload':193C 'use':61C 'user':255C,256C,313C 'vector':269C 'vulner':8A,160C 'way':106C 'web':174C,181C,189C,200C,213C 'wish':257C 'within':198C 'would':153C","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2020-02-24T22:15:12+00:00","kev":{"dateAdded":"2022-03-03","dueDate":"2022-03-17","requiredAction":"Apply updates per vendor instructions.","knownRansomwareCampaignUse":"Unknown"},"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvss_by":"nvd@nist.gov","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2020-1938","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2020-1938","severity":null,"published_at":"2022-03-03T00:00:00+00:00","modified_at":null,"first_seen_at":"2026-10-23T19:11:52+00:00","fetched_at":"2026-10-25T15:39:43+00:00","note":null},{"source":"epss","external_id":"CVE-2020-1938","url":"https://api.first.org/data/v1/epss?cve=CVE-2020-1938","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-23T19:13:44+00:00","fetched_at":"2026-10-23T19:13:44+00:00","note":null},{"source":"nvd","external_id":"CVE-2020-1938","url":"https://nvd.nist.gov/vuln/detail/CVE-2020-1938","severity":null,"published_at":"2020-02-24T22:15:12+00:00","modified_at":"2026-08-25T16:28:27+00:00","first_seen_at":"2026-10-23T21:57:35+00:00","fetched_at":"2026-10-23T21:57:35+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"}