{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-64389 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-64389 is a high-severity authentication bypass vulnerability in Linux kernel, published on 25 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-2026-64389 and fix it if it is affected.\n\nWhat it is: CVE-2026-64389 is a high-severity authentication bypass vulnerability in Linux kernel, published on 25 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-2026-64389 in the wild and no public exploit code.\n\nAffected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.\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-2026-64389/ (Markdown: https://insights.sbomify.com/CVE-2026-64389/index.md)","id":"CVE-2026-64389","markdown":"https://insights.sbomify.com/CVE-2026-64389/index.md","name":"CVE-2026-64389","record":{"aliases":["BELL-CVE-2026-64389","DEBIAN-CVE-2026-64389","GHSA-fxvf-vm38-6pxw","ROOT-OS-DEBIAN-12-CVE-2026-64389","ROOT-OS-DEBIAN-13-CVE-2026-64389","ROOT-OS-UBUNTU-2204-CVE-2026-64389","UBUNTU-CVE-2026-64389"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["privilege_escalation","data_read"],"network_reachable":"yes","non_default_config":false,"product_category":"Linux kernel SMB server","requires_auth":"none","summary":"Attackers can bypass NTLMv2 authentication in ksmbd to modify session keys, potentially gaining unauthorized access or privileges.","user_interaction":"not_required","vuln_class":"auth_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":8.2,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H","version":"3.1"},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: validate NTLMv2 response before updating session key\n\nksmbd_auth_ntlmv2() derives the NTLMv2 session key into\nsess-\u003esess_key before it verifies the NTLMv2 response.\nksmbd_decode_ntlmssp_auth_blob() then continues into KEY_XCH even\nwhen ksmbd_auth_ntlmv2() failed.\n\nWith SMB3 multichannel binding, the failed authentication operates on\nan existing session and the session setup error path does not expire\nbinding sessions. A client can send a binding session setup with a\nbad NT proof and KEY_XCH and still modify sess-\u003esess_key before\nSTATUS_LOGON_FAILURE is returned.\n\nRelevant path:\n\n  smb2_sess_setup()\n    -\u003e conn-\u003ebinding = true\n    -\u003e ntlm_authenticate()\n       -\u003e session_user()\n       -\u003e ksmbd_decode_ntlmssp_auth_blob()\n          -\u003e ksmbd_auth_ntlmv2()\n             -\u003e calc_ntlmv2_hash()\n             -\u003e hmac_md5_usingrawkey(..., sess-\u003esess_key)\n             -\u003e crypto_memneq() returns mismatch\n          -\u003e KEY_XCH arc4_crypt(..., sess-\u003esess_key, ...)\n    -\u003e out_err without expiring the binding session\n\nDerive the base session key into a local buffer and copy it to\nsess-\u003esess_key only after the proof matches. Return immediately on\nauthentication failure so KEY_XCH is only processed after successful\nauthentication.","ecosystems":[],"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":"ksmbd: validate NTLMv2 response before updating session key","id":"CVE-2026-64389","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"auth_bypass","year":"2026"},"n_packages":0,"n_references":5,"next":{"headline":"ksmbd: track the connection owning a byte-range lock","id":"CVE-2026-64390"},"packages":[],"prev":{"headline":"smb/client: fix chown/chgrp with SMB3 POSIX Extensions","id":"CVE-2026-64388"},"products":["Linux"],"published":"2026-07-25","related":[{"cvss_score":8.8,"headline":"Linux Kernel Out-of-Bounds Write","id":"CVE-2026-53266","kev_date_added":"2026-09-18","published":"2026-06-25"},{"cvss_score":8.8,"headline":"Linux Kernel Improper Input Validation","id":"CVE-2013-6282","kev_date_added":"2022-09-15","published":"2013-11-19"},{"cvss_score":8.4,"headline":"Linux Kernel Heap-Based Buffer Overflow","id":"CVE-2022-0185","kev_date_added":"2024-08-21","published":"2022-02-11"},{"cvss_score":8.4,"headline":"Linux Kernel Privilege Escalation","id":"CVE-2013-2094","kev_date_added":"2022-09-15","published":"2013-05-14"},{"cvss_score":7.8,"headline":"Linux Kernel Unspecified","id":"CVE-2026-53362","kev_date_added":"2026-08-27","published":"2026-07-04"},{"cvss_score":7.8,"headline":"Linux Kernel Missing Initialization of a Variable","id":"CVE-2026-46300","kev_date_added":"2026-10-28","published":"2026-05-23"},{"cvss_score":7.8,"headline":"Linux Kernel Race Condition","id":"CVE-2025-39964","kev_date_added":"2026-09-18","published":"2025-10-13"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-10-21","vendors":["Linux"]},"summary":"Attackers can bypass NTLMv2 authentication in ksmbd to modify session keys, potentially gaining unauthorized access or privileges.","url":"https://insights.sbomify.com/CVE-2026-64389/"}