{"answers":{"affected":"1 open source package ship an affected version, including bandit.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-65623 exists.","fix":"Upgrade bandit to 1.12.1 or later.","what":"CVE-2026-65623 is a high-severity denial of service vulnerability in mtrudel bandit, published on 24 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-2026-65623 and fix it if it is affected.\n\nWhat it is: CVE-2026-65623 is a high-severity denial of service vulnerability in mtrudel bandit, published on 24 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-2026-65623 exists.\n\nAffected packages and fixed versions:\n- bandit (Hex): affected from 1.11.0; fixed in 1.12.1\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-2026-65623/ (Markdown: https://insights.sbomify.com/CVE-2026-65623/index.md)","id":"CVE-2026-65623","markdown":"https://insights.sbomify.com/CVE-2026-65623/index.md","name":"CVE-2026-65623","record":{"aliases":["EEF-CVE-2026-65623","GHSA-vg8x-66vg-5pxh"],"analysis":{"component_type":"server_software","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"Elixir web server","requires_auth":"none","summary":"Unauthenticated attackers can cause CPU exhaustion and denial of service by sending fragmented WebSocket messages to the Bandit server.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"EEF","cpe":[],"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-407","name":"Inefficient Algorithmic Complexity"}],"description":"Inefficient Algorithmic Complexity vulnerability in mtrudel bandit allows unauthenticated remote denial of service via CPU exhaustion during WebSocket fragment reassembly.\n\nThe size guard 'Elixir.Bandit.WebSocket.Connection':oversize_message?/2 called from handle_frame/3 in lib/bandit/websocket/connection.ex appends each non-final continuation frame to a left-nested iolist and then re-measures the entire accumulated buffer with IO.iodata_length/1 on every frame. Because the buffer grows by one element per frame and is fully re-traversed each time, reassembly work is quadratic (O(n^2)) in the number of continuation frames.\n\nThe max_fragmented_message_size limit (default 8 MB) bounds total bytes but not frame count, and each frame can carry as little as one payload byte, so an attacker can send millions of tiny continuation frames using modest bandwidth to pin a CPU core for minutes to hours. Many concurrent connections can starve the whole server of CPU, denying service to legitimate users. The WebSocket read timeout does not help, because it is an idle timeout evaluated between reads and cannot preempt the synchronous reassembly work spent inside a single callback.\n\nThis issue affects bandit: from 1.11.0 before 1.12.1.","ecosystems":["Hex"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":true,"headline":"Quadratic CPU blow-up reassembling fragmented WebSocket messages in Bandit","id":"CVE-2026-65623","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Hex","product":null,"products":[],"type":"denial_of_service","year":"2026"},"n_packages":1,"n_references":4,"next":{"headline":"Cowboy HTTP/1.1 max_headers Bypass via Duplicate Header Names Enables Memory Exhaustion","id":"CVE-2026-65624"},"packages":[{"ecosystem":"Hex","fixed":["1.12.1"],"introduced":["1.11.0"],"last_affected":[],"package":"bandit","purl":"pkg:hex/bandit","source":"EEF-CVE-2026-65623"}],"prev":{"headline":"Improper URL validation when handling specific URLs Pub, Terraform and Docker packages might lead to SSRF vulnerability","id":"CVE-2026-65618"},"products":["bandit"],"published":"2026-07-24","related":[],"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":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"yes","exploitation":"poc","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-07-25","vendors":["mtrudel"]},"summary":"Unauthenticated attackers can cause CPU exhaustion and denial of service by sending fragmented WebSocket messages to the Bandit server.","url":"https://insights.sbomify.com/CVE-2026-65623/"}