{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2026-89689 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-89689 is a critical use after free vulnerability in Linux, published on 11 Sep 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-2026-89689 and fix it if it is affected.\n\nWhat it is: CVE-2026-89689 is a critical use after free vulnerability in Linux, published on 11 Sep 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-2026-89689 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-2026-89689/ (Markdown: https://insights.sbomify.com/CVE-2026-89689/index.md)","id":"CVE-2026-89689","markdown":"https://insights.sbomify.com/CVE-2026-89689/index.md","name":"CVE-2026-89689","record":{"aliases":["BELL-CVE-2026-89689","DEBIAN-CVE-2026-89689","GHSA-49vg-hxcf-g87m","UBUNTU-CVE-2026-89689"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["code_execution","denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"Linux kernel NFS server","requires_auth":"none","summary":"A use-after-free vulnerability in the Linux kernel NFS server allows attackers to corrupt memory, potentially leading to code execution or system crashes.","user_interaction":"not_required","vuln_class":"use_after_free"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[],"cvss":{"score":9.8,"severity":"critical","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: don't free session slots that are still in use\n\nnfsd4_sequence() can free the very slot it is currently processing.\nWhen the session shrinker has reduced se_target_maxslots below\nse_fchannel.maxreqs, the shrink path checks three conditions before\ncalling free_session_slots():\n\n  1. se_target_maxslots \u003c maxreqs  (shrink was advertised)\n  2. slot-\u003esl_generation == se_slot_gen  (slot is up-to-date)\n  3. seq-\u003emaxslots \u003c= se_target_maxslots  (client acknowledges)\n\nHowever, seq-\u003eslotid is never checked against se_target_maxslots.\nA client using a slot in the range [se_target_maxslots, maxreqs) can\nsatisfy all three conditions: its slot has the current generation\n(set by a prior SEQUENCE), and it sends sa_highest_slotid \u003c=\nse_target_maxslots to acknowledge the reduction.\n\nfree_session_slots() then kfrees every slot at index \u003e=\nse_target_maxslots, including the caller's own slot. The function\ncontinues to write sl_seqid, sl_flags, sl_generation, and stores the\ndangling pointer in cstate-\u003eslot. Later, nfsd4_store_cache_entry()\ncopies up to maxresp_cached bytes of the compound reply into the freed\nsl_data[] array, corrupting whatever slab object now occupies that\naddress.\n\nAdditionally, a concurrent thread processing SEQUENCE on a different\nhigh-numbered slot can have its slot freed out from under it.\nNFSD4_SLOT_INUSE is set under nn-\u003eclient_lock before the lock is\nreleased, so any concurrent thread past SEQUENCE will have its slot\nmarked. However, free_session_slots() does not check NFSD4_SLOT_INUSE\nbefore freeing.\n\nFix both problems by:\n 1. Checking that the current request's slotid is below the shrink\n    boundary.\n 2. Scanning slots in the to-be-freed range for NFSD4_SLOT_INUSE and\n    deferring the shrink if any are active.","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":"nfsd: don't free session slots that are still in use","id":"CVE-2026-89689","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"use_after_free","year":"2026"},"n_packages":0,"n_references":3,"next":{"headline":"nfsd: defer vfree of compound ops to fix rpc_status UAF","id":"CVE-2026-89690"},"packages":[],"prev":{"headline":"nfsd: drop the stateid, not the stateowner, on seqid_op replay retry","id":"CVE-2026-89688"},"products":["Linux"],"published":"2026-09-11","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":"2026-10-19","vendors":["Linux"]},"summary":"A use-after-free vulnerability in the Linux kernel NFS server allows attackers to corrupt memory, potentially leading to code execution or system crashes.","url":"https://insights.sbomify.com/CVE-2026-89689/"}