{"schemaVersion":3,"id":"CVE-2026-44429","aliases":["CGA-ggq7-7f6f-7cvg","CGA-xx2p-jg37-gv3w","GHSA-rqv2-m695-f8j4","GO-2026-5637"],"status":"published","duplicateOf":null,"title":null,"description":"The MCP Registry provides MCP clients with a list of MCP servers, like an app store for MCP servers. Prior to 1.7.7, the public catalogue UI served at GET / (file internal/api/handlers/v0/ui_index.html) is vulnerable to stored cross-site scripting via the server.websiteUrl field of any published server.json. Server-side validation in internal/validators/validators.go (validateWebsiteURL) only checks that the URL parses, is absolute, and uses the https scheme; it does not reject quote characters. Client-side, the value is interpolated into a double-quoted href attribute via innerHTML, using a homegrown escapeHtml helper that performs the standard textContent → innerHTML round-trip. Per the HTML serialisation algorithm, that round-trip encodes only &, <, > and U+00A0 inside text nodes — it does not encode \" or '. A literal \" in websiteUrl therefore breaks out of the href attribute, allowing arbitrary on* event handlers to be appended to the same <a> element. The Content-Security-Policy on / is script-src 'self' 'unsafe-inline' https://cdn.tailwindcss.com, so the injected event handlers execute. Any user able to obtain a publish token (e.g. via POST /v0/auth/github-at with their own GitHub account, or POST /v0/auth/none on a deployment that has anonymous auth enabled) can plant a poisoned record visible to every visitor of the registry homepage. This vulnerability is fixed in 1.7.7.","dates":{"published":"2026-05-14T21:05:56.130Z","modified":"2026-05-15T14:20:27.564Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":5.4,"severity":"medium","version":"3.1","versionLabel":"v3.1","source":"NVD","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","computed":false,"selection":"backend-summary"},"metrics":[{"version":"4.0","versionLabel":"v4.0","source":"CVE.org","score":5.1,"severity":"medium","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:N/SI:L/SA:L","exploitability":null,"impact":null,"computed":false},{"version":"4.0","versionLabel":"v4.0","source":"OSV · Wolfi","score":5.1,"severity":"medium","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:N/SI:L/SA:L","exploitability":null,"impact":null,"computed":true},{"version":"4.0","versionLabel":"v4.0","source":"OSV · Go","score":5.1,"severity":"medium","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:N/SI:L/SA:L","exploitability":null,"impact":null,"computed":true},{"version":"3.1","versionLabel":"v3.1","source":"OSV · Go","score":5.4,"severity":"medium","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","exploitability":5.9,"impact":4.5,"computed":true},{"version":"4.0","versionLabel":"v4.0","source":"OSV · Chainguard","score":5.1,"severity":"medium","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:N/SI:L/SA:L","exploitability":null,"impact":null,"computed":true},{"version":"4.0","versionLabel":"v4.0","source":"NVD","score":5.1,"severity":"medium","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:N/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"NVD","score":5.4,"severity":"medium","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.00239,"percentile":0.13988,"severity":"low","asOf":"2026-10-20T00:00:00.000Z","change":{"pp":0.07200000000000001,"baselineDate":"2026-09-20T00:00:00.000Z","baselineScore":0.00167},"history":[{"date":"2026-09-14T00:00:00.000Z","score":0.00167,"percentile":null},{"date":"2026-09-15T00:00:00.000Z","score":0.00167,"percentile":null},{"date":"2026-09-16T00:00:00.000Z","score":0.00167,"percentile":null},{"date":"2026-09-17T00:00:00.000Z","score":0.00167,"percentile":null},{"date":"2026-09-18T00:00:00.000Z","score":0.00167,"percentile":null},{"date":"2026-09-19T00:00:00.000Z","score":0.00167,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.00167,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.00167,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.00167,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.00167,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00239,"percentile":0.13988}],"last30":[{"date":"2026-09-20T00:00:00.000Z","score":0.00167,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.00167,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.00167,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.00167,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00239,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.00239,"percentile":0.13988}]},"kev":{"state":"not-listed","entries":[],"listedCount":0,"totalCatalogs":3,"catalogs":[{"source":"cisa","label":"CISA","listed":false,"entry":null},{"source":"enisa","label":"ENISA","listed":false,"entry":null},{"source":"circl","label":"CIRCL","listed":false,"entry":null}]},"ransomware":{"state":"none-recorded","sources":[]},"exploits":[{"id":"GITHUB_MODELCONTEXTPROTOCOL_REGISTRY","name":"Registry","source":"github","url":"https://github.com/modelcontextprotocol/registry/security/advisories/GHSA-rqv2-m695-f8j4","maturity":"poc","reliabilityScore":0.3,"verified":false,"type":null,"platforms":[],"requiresAuth":null,"exploitdb":null,"metasploit":null}],"exploitCount":1,"weaknesses":[{"id":"CWE-79","name":"Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')","description":"The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.","type":"weakness","status":"Stable","abstraction":"Base","likelihoodOfExploit":"High","url":"https://cwe.mitre.org/data/definitions/79.html"},{"id":"CWE-116","name":"Improper Encoding or Escaping of Output","description":"The product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved.","type":"weakness","status":"Draft","abstraction":"Class","likelihoodOfExploit":"High","url":"https://cwe.mitre.org/data/definitions/116.html"}],"affected":[{"vendor":"chainguard","product":"goreleaser","name":"goreleaser","label":"goreleaser","ecosystem":"Chainguard","cpePart":null,"purl":"pkg:apk/chainguard/goreleaser","purlType":"apk","versions":[{"text":"< 2.15.4-r1","noFixRecorded":false,"fixedIn":null},{"text":"< 2.15.4-r2","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 2.15.4-r1 | < 2.15.4-r2","eol":null,"hubHref":null},{"vendor":"wolfi","product":"goreleaser","name":"goreleaser","label":"goreleaser","ecosystem":"Wolfi","cpePart":null,"purl":"pkg:apk/wolfi/goreleaser","purlType":"apk","versions":[{"text":"< 2.15.4-r1","noFixRecorded":false,"fixedIn":null},{"text":"< 2.15.4-r2","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 2.15.4-r1 | < 2.15.4-r2","eol":null,"hubHref":null},{"vendor":"github.com/modelcontextprotocol","product":"registry","name":"github.com/modelcontextprotocol/registry","label":"registry","ecosystem":"Go","cpePart":null,"purl":"pkg:golang/github.com/modelcontextprotocol/registry","purlType":"golang","versions":[{"text":"< 1.7.7","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 1.7.7","eol":null,"hubHref":null},{"vendor":"lfprojects","product":"mcp_registry","name":"mcp registry","label":"mcp_registry","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"< 1.7.7","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 1.7.7","eol":null,"hubHref":"/vendor/lfprojects/mcp_registry"},{"vendor":"modelcontextprotocol","product":"registry","name":"registry","label":"registry","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"< 1.7.7","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 1.7.7","eol":null,"hubHref":"/vendor/modelcontextprotocol/registry"}],"affectedCount":5,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://github.com/modelcontextprotocol/registry/security/advisories/GHSA-rqv2-m695-f8j4","label":"github.com/modelcontextprotocol/registry/security/advisories/GHSA-rqv2-m695-f8j4","hostname":"github.com","tags":["X Refsource CONFIRM","Advisory","WEB","Exploit","Mitigation","Vendor Advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44429.json","label":"github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44429.json","hostname":"github.com","tags":["Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-44429","label":"nvd.nist.gov/vuln/detail/CVE-2026-44429","hostname":"nvd.nist.gov","tags":["Advisory"]},{"url":"https://github.com/modelcontextprotocol/registry/pull/1249","label":"github.com/modelcontextprotocol/registry/pull/1249","hostname":"github.com","tags":["WEB","FIX"]},{"url":"https://github.com/modelcontextprotocol/registry/commit/78b7bbde07948049b916d76b4769faee461ff930","label":"github.com/modelcontextprotocol/registry/commit/78b7bbde07948049b916d76b4769faee461ff930","hostname":"github.com","tags":["WEB","FIX"]},{"url":"https://github.com/modelcontextprotocol/registry","label":"github.com/modelcontextprotocol/registry","hostname":"github.com","tags":["PACKAGE"]},{"url":"https://github.com/modelcontextprotocol/registry/releases/tag/v1.7.7","label":"github.com/modelcontextprotocol/registry/releases/tag/v1.7.7","hostname":"github.com","tags":["WEB"]}],"lineage":{"upstream":[],"downstream":["OPENSUSE-SU-2026:21483-1"],"duplicates":[],"related":["CGA-MM3G-43JF-37G3","OPENSUSE-SU-2026:21483-1"]},"timeline":[{"kind":"published","date":"2026-05-14T21:05:56.130Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-05-15T14:20:27.564Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":32,"level":"medium","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-20T23:40:01.421Z","stale":false,"partial":false}}