{"id":"GHSA-4595-rvpx-4q34","revision":null,"records":[{"revision":"035e1e47f5224353be86084bbc12043e","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-61554","aliases":[],"title":"emp3r0r has an unauthenticated HTTP Polling DoS","description":"emp3r0r is a C2 designed by Linux users for Linux environments. Prior to version 4.2.5, the `http_poll` C2 transport accepts attacker-controlled HTTP polling sessions before CBOR `MsgAuth` authentication is completed. A remote unauthenticated attacker can create arbitrary polling sessions and send request bodies that are forwarded into the C2 dispatch path. This can consume server resources and trigger pre-auth C2 processing. Version 4.2.5 patches the issue.","state":0,"publishedAt":"2026-09-15T20:48:05.156+00:00","modifiedAt":"2026-09-16T17:59:54.763+00:00","affected":[{"ecosystem":"Vendor product","name":"emp3r0r","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"jm33-m0\",\n                    \"product\": \"emp3r0r\",\n                    \"versions\": [\n                        {\n                            \"version\": \"< 4.2.5\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5,"severity":"HIGH"}],"references":["https://github.com/jm33-m0/emp3r0r/security/advisories/GHSA-4595-rvpx-4q34","https://github.com/jm33-m0/emp3r0r/releases/tag/v4.2.5"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-61554","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-61554","identifiers":["CVE-2026-61554"]},"retained":false,"historicalAffected":[]},{"revision":"6dfba8900eb043c5979d9210cbd818e2","observedAt":"2026-11-11T15:02:40.968+00:00","statement":{"source":"euvd","id":"EUVD-2026-79996","aliases":["CVE-2026-61554","GHSA-4595-rvpx-4q34"],"title":"emp3r0r is a C2 designed by Linux users for Linux environments. Prior to version 4.2.5, the `http_poll` C2 transport accepts attacker-controlled HTTP polling sessions before CBOR `MsgAuth` authentication is completed. A remote unauthenticat…","description":"emp3r0r is a C2 designed by Linux users for Linux environments. Prior to version 4.2.5, the `http_poll` C2 transport accepts attacker-controlled HTTP polling sessions before CBOR `MsgAuth` authentication is completed. A remote unauthenticated attacker can create arbitrary polling sessions and send request bodies that are forwarded into the C2 dispatch path. This can consume server resources and trigger pre-auth C2 processing. Version 4.2.5 patches the issue.","state":0,"publishedAt":null,"modifiedAt":null,"affected":[],"metrics":[{"system":"EUVD CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5,"severity":null}],"references":["https://github.com/jm33-m0/emp3r0r/security/advisories/GHSA-4595-rvpx-4q34","https://github.com/jm33-m0/emp3r0r/releases/tag/v4.2.5"],"sourceUrl":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-79996","license":"ENISA EUVD · source terms and attribution apply","enrichment":{"sourceStatus":null,"weaknesses":[],"productCriteria":[],"sourceDates":{"datePublished":"Sep 15, 2026, 8:48:05 PM","dateUpdated":"Sep 16, 2026, 5:59:54 PM"},"relatedAdvisories":[],"note":"EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON."},"key":"euvd:EUVD-2026-79996","identifiers":["EUVD-2026-79996","CVE-2026-61554","GHSA-4595-rvpx-4q34"]},"retained":false,"historicalAffected":[]},{"revision":"5486c8c0791d469f925813c96c43aa41","observedAt":"2026-10-25T14:19:22.811+00:00","statement":{"source":"nvd","id":"CVE-2026-61554","aliases":[],"title":"emp3r0r is a C2 designed by Linux users for Linux environments. Prior to version 4.2.5, the `http_poll` C2 transport accepts attacker-controlled HTTP polling sessions before CBOR `MsgAuth` authentication is completed. A remote unauthenticat…","description":"emp3r0r is a C2 designed by Linux users for Linux environments. Prior to version 4.2.5, the `http_poll` C2 transport accepts attacker-controlled HTTP polling sessions before CBOR `MsgAuth` authentication is completed. A remote unauthenticated attacker can create arbitrary polling sessions and send request bodies that are forwarded into the C2 dispatch path. This can consume server resources and trigger pre-auth C2 processing. Version 4.2.5 patches the issue.","state":0,"publishedAt":"2026-09-15T21:16:41.223+00:00","modifiedAt":"2026-09-30T17:51:56.193+00:00","affected":[],"metrics":[{"system":"CVSS 3.1 · security-advisories@github.com · Secondary","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5,"severity":"HIGH"}],"references":["https://github.com/jm33-m0/emp3r0r/releases/tag/v4.2.5","https://github.com/jm33-m0/emp3r0r/security/advisories/GHSA-4595-rvpx-4q34"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-61554","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Deferred","weaknesses":["CWE-400"],"productCriteria":[],"sourceDates":{"published":"2026-09-15T21:16:41.223","lastModified":"2026-09-30T17:51:56.193"},"relatedAdvisories":[],"note":"NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2026-61554","identifiers":["CVE-2026-61554"]},"retained":false,"historicalAffected":[]},{"revision":"1ef51c3d1e27471c8f52454979d0d373","observedAt":"2026-10-24T13:19:41.952+00:00","statement":{"source":"osv","id":"GHSA-4595-rvpx-4q34","aliases":["CVE-2026-61554","GO-2026-6487"],"title":"emp3r0r has an unauthenticated HTTP Polling DoS","description":"### Summary\nThe `http_poll` C2 transport accepts attacker-controlled HTTP polling sessions before CBOR `MsgAuth` authentication is completed. A remote unauthenticated attacker can create arbitrary polling sessions and send request bodies that are forwarded into the C2 dispatch path. This can consume server resources and trigger pre-auth C2 processing.\n\n### Details\nThe plain HTTP C2 server starts the HTTP polling listener and forwards requests into `HandleHTTPServerSession`:\n```go\n// core/internal/cc/server/c2_http_server.go\nmux.HandleFunc(c2Path, func(w http.ResponseWriter, req *http.Request) {\n    stream, err := transport.HandleHTTPServerSession(w, req, &live.RuntimeConfig.MalleableC2)\n    ...\n    if stream != nil {\n        go cborStreamAccept(transport.NewStreamTransport(stream, req.RemoteAddr))\n    }\n})\n```\nThe HTTP polling handler accepts an attacker-supplied `sessionID` and `init=1` cookie, then creates and stores a server-side stream before authentication:\n\n```go\n// core/internal/transport/c2channel_http.go\nif isInit {\n    stream = newHTTPServerStream(sessionID)\n    w.WriteHeader(http.StatusOK)\n    return stream, nil\n}\n```\nPOST bodies for that unauthenticated session are read and queued before CBOR authentication rejects them:\n```go\n// core/internal/transport/c2channel_http.go\ncase http.MethodPost:\n    data, err := io.ReadAll(req.Body)\n    if err == nil && len(data) > 0 {\n        select {\n        case stream.readCh <- data:\n            w.WriteHeader(http.StatusOK)\n        ...\n        }\n    }\n```\nAuthentication only happens later in the C2 dispatch layer:\n```go\n// core/internal/cc/server/dispatcher.go\nsecureConn := transport.NewSecureConn(t)\n...\nn, err := secureConn.Read(authFrame)\n```\n\n### PoC\n1. Start the C2 server in a lab environment with the HTTP polling transport exposed, for example with `--http-port 12345`.\n2. Send an unauthenticated HTTP POST to the default polling path `/api/v1/telemetry` with a random `sessionID` cookie and the `init=1` cookie value.\n3. Send a second unauthenticated HTTP POST to `/api/v1/telemetry` using the same `sessionID`, with a request body containing repeated `A` bytes.\n4. Observe that both unauthenticated requests return HTTP `200`.\n5. Observe the C2 server log showing attacker-controlled bytes reaching the encrypted C2 frame parser, for example: `read: invalid encrypted chunk length: 1094795585`.\n6. `1094795585` is `0x41414141`, which corresponds to `AAAA`, confirming unauthenticated request body data reached `cborProtocolDispatch` before CBOR `MsgAuth` authentication.\n7. Repeat the request sequence concurrently to increase server resource usage and log volume.\n\n### Impact\n- Remote unauthenticated attackers can create arbitrary HTTP polling sessions.\n- Attacker-controlled request bodies reach pre-auth C2 dispatch handling.\n- Repeated requests can consume server memory, goroutines, request handling capacity, and log volume.\n- C2 service availability and operator reliability may be degraded under sustained traffic.\n\n### Remediation\n- Require authentication before creating long-lived HTTP polling sessions.\n- Do not forward request bodies into the C2 stream before validation.\n- Add strict request body limits.","state":0,"publishedAt":"2026-09-15T20:47:17+00:00","modifiedAt":"2026-09-28T17:10:43.7700593+00:00","affected":[{"ecosystem":"Go","name":"github.com/jm33-m0/emp3r0r/core","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"},{"kind":"fixed","version":"0.0.0-20260531142011-aed3d81641ab"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[{"system":"CVSS_V3","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":null,"severity":null},{"system":"Publisher rating","vector":null,"score":null,"severity":"HIGH"}],"references":["https://github.com/jm33-m0/emp3r0r/security/advisories/GHSA-4595-rvpx-4q34","https://github.com/jm33-m0/emp3r0r","https://github.com/jm33-m0/emp3r0r/releases/tag/v4.2.5"],"sourceUrl":"https://github.com/advisories/GHSA-4595-rvpx-4q34","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-4595-rvpx-4q34","identifiers":["GHSA-4595-rvpx-4q34","CVE-2026-61554","GO-2026-6487"]},"retained":false,"historicalAffected":[]},{"revision":"8f4ffbe2f9a34a02b391d4a2b162f12d","observedAt":"2026-10-24T13:19:41.952+00:00","statement":{"source":"osv","id":"GO-2026-6487","aliases":["CVE-2026-61554","GHSA-4595-rvpx-4q34"],"title":"emp3r0r has an unauthenticated HTTP Polling DoS in github.com/jm33-m0/emp3r0r/core","description":"emp3r0r has an unauthenticated HTTP Polling DoS in github.com/jm33-m0/emp3r0r/core","state":0,"publishedAt":"2026-09-28T16:43:40+00:00","modifiedAt":"2026-09-28T17:00:16.5483358+00:00","affected":[{"ecosystem":"Go","name":"github.com/jm33-m0/emp3r0r/core","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"},{"kind":"fixed","version":"0.0.0-20260531142011-aed3d81641ab"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[],"references":["https://github.com/jm33-m0/emp3r0r/security/advisories/GHSA-4595-rvpx-4q34","https://github.com/jm33-m0/emp3r0r/releases/tag/v4.2.5"],"sourceUrl":"https://osv.dev/vulnerability/GO-2026-6487","license":"OSV · upstream source license applies","key":"osv:GO-2026-6487","identifiers":["GO-2026-6487","CVE-2026-61554","GHSA-4595-rvpx-4q34"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. 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