{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2026-89928 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-89928 is a high-severity use after free vulnerability in Linux, published on 16 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-89928 and fix it if it is affected.\n\nWhat it is: CVE-2026-89928 is a high-severity use after free vulnerability in Linux, published on 16 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-89928 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-2026-89928/ (Markdown: https://insights.sbomify.com/CVE-2026-89928/index.md)","id":"CVE-2026-89928","markdown":"https://insights.sbomify.com/CVE-2026-89928/index.md","name":"CVE-2026-89928","record":{"aliases":["BELL-CVE-2026-89928","DEBIAN-CVE-2026-89928","GHSA-f7hc-2wxr-4jfg","UBUNTU-CVE-2026-89928"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["code_execution","privilege_escalation"],"network_reachable":"adjacent_or_local","non_default_config":true,"product_category":"Linux kernel KVM","requires_auth":"low_privilege","summary":"A race condition in KVM's lockless rmap walk allows a use-after-free, potentially enabling local attackers to execute code or escalate privileges.","user_interaction":"not_required","vuln_class":"use_after_free"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[],"cvss":{"score":8.8,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","version":"3.1"},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: x86/mmu: Consume the locked rmap value in the lockless rmap walk\n\n__kvm_rmap_lock() deliberately elides the rmap lock when it observes an\nempty rmap.  In that case kvm_rmap_lock_readonly() also re-enables\npreemption and returns zero, so the caller holds neither the rmap lock\nnor a preemption reference.  The elision documents the invariant it\nrelies on:\n\n\t * Elide the lock if the rmap is empty, as lockless walkers (read-only\n\t * mode) don't need to (and can't) walk an empty rmap, nor can they add\n\t * entries to the rmap.  I.e. the only paths that process empty rmaps\n\t * do so while holding mmu_lock for write, and are mutually exclusive.\n\nkvm_rmap_age_gfn_range() ignores the returned value and unconditionally\nenters for_each_rmap_spte_lockless().  The iterator started with\nrmap_get_first(), which re-reads rmap_head-\u003eval rather than using the\nvalue returned by the lock.  If a writer populates the rmap between the\nlock's read and the iterator's re-read, the aging path walks the newly\ninstalled rmap without holding its lock.\n\nFor a KVM_RMAP_MANY rmap this leaves the walker following a\npte_list_desc chain that it never locked.  A writer holding mmu_lock for\nwrite may free that chain (e.g. kvm_zap_all_rmap_sptes() on the recycle\npath, or any rmap zap) via kmem_cache_free() while the walk is in\nprogress, giving a slab use-after-free.  Nothing serialises the two: the\naging path runs without mmu_lock when CONFIG_KVM_MMU_LOCKLESS_AGING=y,\nand the rmap lock that would otherwise exclude the writer was elided.\nBecause the empty path re-enables preemption, the interval between the\ntwo reads can span an arbitrary scheduling delay.\n\nFix the class of bug by having the lockless walk consume the value\nreturned by the lock instead of re-reading the rmap.  Split\nrmap_get_first() into __rmap_get_first(), which starts an iterator from\nan already-read rmap value, and make for_each_rmap_spte_lockless() take\nthat value and call __rmap_get_first() directly.\nkvm_rmap_age_gfn_range() passes the value returned by\nkvm_rmap_lock_readonly(): when the lock was elided the value is zero,\n__rmap_get_first() returns NULL, and the walk is skipped.  No lockless\nwalker re-reads the rmap, so the lock-elision invariant cannot be\nviolated, and no lock()-without-paired-unlock() path is added to the\naging code.","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":"KVM: x86/mmu: Consume the locked rmap value in the lockless rmap walk","id":"CVE-2026-89928","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":"KVM: nVM: Ensure INVVPID is emulated on the correct physical CPU","id":"CVE-2026-89929"},"packages":[],"prev":{"headline":"KVM: x86: hyper-v: Clamp stimer deadline to avoid livelock","id":"CVE-2026-89927"},"products":["Linux"],"published":"2026-09-16","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 race condition in KVM's lockless rmap walk allows a use-after-free, potentially enabling local attackers to execute code or escalate privileges.","url":"https://insights.sbomify.com/CVE-2026-89928/"}