{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2026-74521 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-74521 is a critical authentication bypass vulnerability in Linux, published on 15 Aug 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-2026-74521 and fix it if it is affected.\n\nWhat it is: CVE-2026-74521 is a critical authentication bypass vulnerability in Linux, published on 15 Aug 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-2026-74521 in the wild and no public exploit code.\n\nAffected product: Linux. 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-2026-74521/ (Markdown: https://insights.sbomify.com/CVE-2026-74521/index.md)","id":"CVE-2026-74521","markdown":"https://insights.sbomify.com/CVE-2026-74521/index.md","name":"CVE-2026-74521","record":{"aliases":["BELL-CVE-2026-74521","DEBIAN-CVE-2026-74521","GHSA-336h-563m-gwm9","UBUNTU-CVE-2026-74521"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":"Linux kernel SMB server","requires_auth":"none","summary":"An attacker can bypass SMB3 multichannel session binding checks by exploiting incorrect ClientGUID comparison logic in the Linux kernel ksmbd module.","user_interaction":"not_required","vuln_class":"auth_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[],"cvss":{"score":9.1,"severity":"critical","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","version":"3.1"},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: use memcmp() to compare ClientGUIDs\n\nClientGUID is a fixed-size binary value and can contain embedded NUL\nbytes. strncmp() stops comparing at the first NUL byte, so different\nClientGUID values can incorrectly be treated as equal.\n\nUse memcmp() in SMB3 multichannel session binding and\nFSCTL_VALIDATE_NEGOTIATE_INFO to compare all SMB2_CLIENT_GUID_SIZE\nbytes.","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: use memcmp() to compare ClientGUIDs","id":"CVE-2026-74521","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"auth_bypass","year":"2026"},"n_packages":0,"n_references":6,"next":{"headline":"ksmbd: fix use-after-free in __close_file_table_ids()","id":"CVE-2026-74522"},"packages":[],"prev":{"headline":"iommu/iommufd: Fix IOPF group ownership UAF","id":"CVE-2026-74520"},"products":["Linux"],"published":"2026-08-15","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-10-03","vendors":["Linux"]},"summary":"An attacker can bypass SMB3 multichannel session binding checks by exploiting incorrect ClientGUID comparison logic in the Linux kernel ksmbd module.","url":"https://insights.sbomify.com/CVE-2026-74521/"}