{"answers":{"affected":"9 open source packages ship an affected version, including phoenix. It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-56811 in the wild and no public exploit code.","fix":"Upgrade phoenix to a fixed version for your release line: 1.5.15, 1.6.17, 1.7.24 or 1.8.9.","what":"CVE-2026-56811 is a high-severity denial of service vulnerability in phoenixframework phoenix, published on 7 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-56811 and fix it if it is affected.\n\nWhat it is: CVE-2026-56811 is a high-severity denial of service vulnerability in phoenixframework phoenix, published on 7 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-56811 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- phoenix (Hex): affected from 0.11.0; fixed in 1.5.15, 1.6.17, 1.7.24, 1.8.9\n- phoenix (Hex): affected from 0.11.0; fixed in 1.5.15\n- phoenix (Hex): affected from 0.11.0; fixed in 1.5.15\n- phoenix (Hex): affected from 1.6.0-rc.0; fixed in 1.6.17\n- phoenix (Hex): affected from 1.6.0-rc.0; fixed in 1.6.17\n- phoenix (Hex): affected from 1.7.0-rc.0; fixed in 1.7.24\n- phoenix (Hex): affected from 1.7.0-rc.0; fixed in 1.7.24\n- phoenix (Hex): affected from 1.8.0-rc.0; fixed in 1.8.9\n- phoenix (Hex): affected from 1.8.0-rc.0; fixed in 1.8.9\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-56811/ (Markdown: https://insights.sbomify.com/CVE-2026-56811/index.md)","id":"CVE-2026-56811","markdown":"https://insights.sbomify.com/CVE-2026-56811/index.md","name":"CVE-2026-56811","record":{"aliases":["EEF-CVE-2026-56811","GHSA-6983-jfq8-485w"],"analysis":{"component_type":"web_application","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"Phoenix web framework","requires_auth":"none","summary":"Unauthenticated attackers can exhaust server processes by joining unlimited channels on a single connection, causing denial of service.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"EEF","cpe":[{"product":"phoenix","vendor":"phoenixframework"}],"cvss":{"score":8.7,"severity":"high","source":"cna","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","version":"4.0"},"cwes":[{"id":"CWE-770","name":"Allocation of Resources Without Limits or Throttling"}],"description":"Allocation of Resources Without Limits or Throttling vulnerability in phoenixframework phoenix (Phoenix.Socket module) allows an unauthenticated attacker to cause a denial of service against any endpoint that mounts a Phoenix socket with a reachable channel transport (WebSocket or LongPoll).\n\nThis vulnerability is associated with program files lib/phoenix/socket.ex and program routine 'Elixir.Phoenix.Socket':handle_in/4.\n\nPhoenix transports do not limit the number of channels that a single transport process may join. Every phx_join message a client sends over one connection starts a persistent channel process, and the socket process accepts an unbounded number of them. A single unauthenticated client can therefore open one WebSocket or LongPoll connection and stream a large number of phx_join messages, spawning hundreds of thousands of channel processes over that one connection and eventually reaching the BEAM maximum process limit. Once the process table is exhausted the virtual machine can no longer start new processes, denying service to legitimate traffic across the whole node. Because the amplification happens inside a single connection, network-layer connection caps and rate limiting do not mitigate it.\n\nThe fix adds a :max_channels_per_transport option (default 100) that bounds the number of channels a single transport process can join, forcing abusive clients to open many connections instead, where external load balancers and reverse proxies can throttle them.\n\nThis issue affects phoenix: from 0.11.0 before 1.5.15, from 1.6.0-rc.0 before 1.6.17, from 1.7.0-rc.0 before 1.7.24, and from 1.8.0-rc.0 before 1.8.9.","ecosystems":["Hex"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"Phoenix transports do not limit channel joins per connection, enabling process-exhaustion denial of service","id":"CVE-2026-56811","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Hex","product":null,"products":[],"type":"denial_of_service","year":"2026"},"n_packages":9,"n_references":8,"next":{"headline":"Phoenix: Presence keys colliding with `Object.prototype` members break existence checks","id":"CVE-2026-56812"},"packages":[{"ecosystem":"Hex","fixed":["1.5.15","1.6.17","1.7.24","1.8.9"],"introduced":["0.11.0","1.6.0-rc.0","1.7.0-rc.0","1.8.0-rc.0"],"last_affected":[],"package":"phoenix","purl":"pkg:hex/phoenix","source":"EEF-CVE-2026-56811"},{"ecosystem":"Hex","fixed":["1.5.15"],"introduced":["0.11.0"],"last_affected":[],"package":"phoenix","purl":null,"source":"GHSA-6983-jfq8-485w"},{"ecosystem":"Hex","fixed":["1.5.15"],"introduced":["0.11.0"],"last_affected":[],"package":"phoenix","purl":"pkg:hex/phoenix","source":"GHSA-6983-jfq8-485w"},{"ecosystem":"Hex","fixed":["1.6.17"],"introduced":["1.6.0-rc.0"],"last_affected":[],"package":"phoenix","purl":null,"source":"GHSA-6983-jfq8-485w"},{"ecosystem":"Hex","fixed":["1.6.17"],"introduced":["1.6.0-rc.0"],"last_affected":[],"package":"phoenix","purl":"pkg:hex/phoenix","source":"GHSA-6983-jfq8-485w"},{"ecosystem":"Hex","fixed":["1.7.24"],"introduced":["1.7.0-rc.0"],"last_affected":[],"package":"phoenix","purl":null,"source":"GHSA-6983-jfq8-485w"},{"ecosystem":"Hex","fixed":["1.7.24"],"introduced":["1.7.0-rc.0"],"last_affected":[],"package":"phoenix","purl":"pkg:hex/phoenix","source":"GHSA-6983-jfq8-485w"},{"ecosystem":"Hex","fixed":["1.8.9"],"introduced":["1.8.0-rc.0"],"last_affected":[],"package":"phoenix","purl":null,"source":"GHSA-6983-jfq8-485w"},{"ecosystem":"Hex","fixed":["1.8.9"],"introduced":["1.8.0-rc.0"],"last_affected":[],"package":"phoenix","purl":"pkg:hex/phoenix","source":"GHSA-6983-jfq8-485w"}],"prev":{"headline":"mint buffers an entire chunked response chunk in memory in Mint.HTTP1.decode_body/5","id":"CVE-2026-56810"},"products":["phoenix"],"published":"2026-07-07","related":[{"cvss_score":7.5,"headline":"Phoenix before 1.6.14 mishandles check_origin wildcarding","id":"CVE-2022-42975","kev_date_added":null,"published":"2022-10-17"},{"cvss_score":6.3,"headline":"Phoenix: Presence keys colliding with `Object.prototype` members break existence checks","id":"CVE-2026-56812","kev_date_added":null,"published":"2026-07-07"},{"cvss_score":6.1,"headline":"Phoenix Arbitrary URL Redirect","id":"CVE-2017-1000163","kev_date_added":null,"published":"2017-11-17"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"Erlang Ecosystem Foundation","prefix":"EEF"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"yes","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-09-24","vendors":["phoenixframework"]},"summary":"Unauthenticated attackers can exhaust server processes by joining unlimited channels on a single connection, causing denial of service.","url":"https://insights.sbomify.com/CVE-2026-56811/"}