{"answers":{"affected":"18 open source packages ship an affected version, including phoenix. It affects 1 product.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-56812 exists.","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-2026-56812 is a medium-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-2026-56812 and fix it if it is affected.\n\nWhat it is: CVE-2026-56812 is a medium-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: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-56812 exists.\n\nAffected packages and fixed versions:\n- phoenix (Hex): affected from 1.2.0-rc.0; fixed in 1.5.15, 1.6.17, 1.7.24, 1.8.9\n- phoenix (Hex): affected from 1.2.0-rc.0; fixed in 1.5.15\n- phoenix (Hex): affected from 1.2.0-rc.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- phoenix (npm): affected from 1.2.0-rc.0; fixed in 1.5.15, 1.6.17, 1.7.24, 1.8.9\n- phoenix (npm): affected from 1.2.0-rc.0; fixed in 1.5.15\n- phoenix (npm): affected from 1.2.0-rc.0; fixed in 1.5.15\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-2026-56812/ (Markdown: https://insights.sbomify.com/CVE-2026-56812/index.md)","id":"CVE-2026-56812","markdown":"https://insights.sbomify.com/CVE-2026-56812/index.md","name":"CVE-2026-56812","record":{"aliases":["EEF-CVE-2026-56812","GHSA-63mc-hw7g-86rr"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"Phoenix JS client","requires_auth":"none","summary":"An attacker can crash the Phoenix JavaScript presence client for all users by using keys that collide with Object.prototype members, causing persistent 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":6.3,"severity":"medium","source":"cna","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N","version":"4.0"},"cwes":[{"id":"CWE-754","name":"Improper Check for Unusual or Exceptional Conditions"}],"description":"Improper Check for Unusual or Exceptional Conditions vulnerability in phoenixframework phoenix (Presence JavaScript client) allows an attacker with ordinary channel access to cause a persistent client-side denial of service against every viewer of a presence channel topic.\n\nThis vulnerability is associated with program files assets/js/phoenix/presence.js and program routines Presence.syncState and Presence.syncDiff.\n\nThe Phoenix JavaScript presence client checks whether a presence already exists with a bare truthiness test (state[key]) instead of an own-property check. Presence keys can be attacker-controlled, because applications track presences under a username or id supplied by the client. A user who joins a channel choosing a key that is an Object.prototype member name (__proto__, constructor, toString, hasOwnProperty, and similar) makes that lookup return JavaScript's built-in Object.prototype instead of undefined. Because the prototype is truthy, the code treats it as an existing presence and reads .metas.map(...) off it, which throws an uncaught TypeError.\n\nThe exception propagates out of the presence message handler, so the local state is never updated and onSync() never fires. Because the malicious key is tracked on the server, it is re-pushed on every presence update and keeps re-throwing, so presence sync stays broken for every viewer of that channel topic until the attacker leaves. Both syncState and syncDiff use the same unsafe existence-check pattern. The impact is limited to the affected topic and is a read-time confusion of the prototype object, not a mutation of Object.prototype (it is not prototype pollution).\n\nThis issue affects phoenix: from 1.2.0-rc.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; phoenix: from 1.2.0-rc.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","npm"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":true,"headline":"Phoenix: Presence keys colliding with `Object.prototype` members break existence checks","id":"CVE-2026-56812","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Hex","product":null,"products":[],"type":"denial_of_service","year":"2026"},"n_packages":18,"n_references":8,"next":{"headline":"Cookie attribute injection in Plug.Conn.Cookies.encode/2","id":"CVE-2026-56813"},"packages":[{"ecosystem":"Hex","fixed":["1.5.15","1.6.17","1.7.24","1.8.9"],"introduced":["1.2.0-rc.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-2026-56812"},{"ecosystem":"Hex","fixed":["1.5.15"],"introduced":["1.2.0-rc.0"],"last_affected":[],"package":"phoenix","purl":null,"source":"GHSA-63mc-hw7g-86rr"},{"ecosystem":"Hex","fixed":["1.5.15"],"introduced":["1.2.0-rc.0"],"last_affected":[],"package":"phoenix","purl":"pkg:hex/phoenix","source":"GHSA-63mc-hw7g-86rr"},{"ecosystem":"Hex","fixed":["1.6.17"],"introduced":["1.6.0-rc.0"],"last_affected":[],"package":"phoenix","purl":null,"source":"GHSA-63mc-hw7g-86rr"},{"ecosystem":"Hex","fixed":["1.6.17"],"introduced":["1.6.0-rc.0"],"last_affected":[],"package":"phoenix","purl":"pkg:hex/phoenix","source":"GHSA-63mc-hw7g-86rr"},{"ecosystem":"Hex","fixed":["1.7.24"],"introduced":["1.7.0-rc.0"],"last_affected":[],"package":"phoenix","purl":null,"source":"GHSA-63mc-hw7g-86rr"},{"ecosystem":"Hex","fixed":["1.7.24"],"introduced":["1.7.0-rc.0"],"last_affected":[],"package":"phoenix","purl":"pkg:hex/phoenix","source":"GHSA-63mc-hw7g-86rr"},{"ecosystem":"Hex","fixed":["1.8.9"],"introduced":["1.8.0-rc.0"],"last_affected":[],"package":"phoenix","purl":null,"source":"GHSA-63mc-hw7g-86rr"},{"ecosystem":"Hex","fixed":["1.8.9"],"introduced":["1.8.0-rc.0"],"last_affected":[],"package":"phoenix","purl":"pkg:hex/phoenix","source":"GHSA-63mc-hw7g-86rr"},{"ecosystem":"npm","fixed":["1.5.15","1.6.17","1.7.24","1.8.9"],"introduced":["1.2.0-rc.0","1.6.0-rc.0","1.7.0-rc.0","1.8.0-rc.0"],"last_affected":[],"package":"phoenix","purl":"pkg:npm/phoenix","source":"EEF-CVE-2026-56812"},{"ecosystem":"npm","fixed":["1.5.15"],"introduced":["1.2.0-rc.0"],"last_affected":[],"package":"phoenix","purl":null,"source":"GHSA-63mc-hw7g-86rr"},{"ecosystem":"npm","fixed":["1.5.15"],"introduced":["1.2.0-rc.0"],"last_affected":[],"package":"phoenix","purl":"pkg:npm/phoenix","source":"GHSA-63mc-hw7g-86rr"},{"ecosystem":"npm","fixed":["1.6.17"],"introduced":["1.6.0-rc.0"],"last_affected":[],"package":"phoenix","purl":null,"source":"GHSA-63mc-hw7g-86rr"},{"ecosystem":"npm","fixed":["1.6.17"],"introduced":["1.6.0-rc.0"],"last_affected":[],"package":"phoenix","purl":"pkg:npm/phoenix","source":"GHSA-63mc-hw7g-86rr"},{"ecosystem":"npm","fixed":["1.7.24"],"introduced":["1.7.0-rc.0"],"last_affected":[],"package":"phoenix","purl":null,"source":"GHSA-63mc-hw7g-86rr"},{"ecosystem":"npm","fixed":["1.7.24"],"introduced":["1.7.0-rc.0"],"last_affected":[],"package":"phoenix","purl":"pkg:npm/phoenix","source":"GHSA-63mc-hw7g-86rr"},{"ecosystem":"npm","fixed":["1.8.9"],"introduced":["1.8.0-rc.0"],"last_affected":[],"package":"phoenix","purl":null,"source":"GHSA-63mc-hw7g-86rr"},{"ecosystem":"npm","fixed":["1.8.9"],"introduced":["1.8.0-rc.0"],"last_affected":[],"package":"phoenix","purl":"pkg:npm/phoenix","source":"GHSA-63mc-hw7g-86rr"}],"prev":{"headline":"Phoenix transports do not limit channel joins per connection, enabling process-exhaustion denial of service","id":"CVE-2026-56811"},"products":["phoenix"],"published":"2026-07-07","related":[{"cvss_score":8.7,"headline":"Phoenix transports do not limit channel joins per connection, enabling process-exhaustion denial of service","id":"CVE-2026-56811","kev_date_added":null,"published":"2026-07-07"},{"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":6.1,"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":"no","exploitation":"poc","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-09-24","vendors":["phoenixframework"]},"summary":"An attacker can crash the Phoenix JavaScript presence client for all users by using keys that collide with Object.prototype members, causing persistent denial of service.","url":"https://insights.sbomify.com/CVE-2026-56812/"}