{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2026-89793 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-89793 is a high-severity 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-2026-89793 and fix it if it is affected.\n\nWhat it is: CVE-2026-89793 is a high-severity 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-2026-89793 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-2026-89793/ (Markdown: https://insights.sbomify.com/CVE-2026-89793/index.md)","id":"CVE-2026-89793","markdown":"https://insights.sbomify.com/CVE-2026-89793/index.md","name":"CVE-2026-89793","record":{"aliases":["AZL-101334","BELL-CVE-2026-89793","DEBIAN-CVE-2026-89793","GHSA-fp98-h54j-vwfj","UBUNTU-CVE-2026-89793"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["privilege_escalation","code_execution"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"An unprivileged daemon can corrupt kernel-written I/O descriptors by upgrading a read-only mmap to writable, potentially leading to privilege escalation or code execution.","user_interaction":"not_required","vuln_class":"privilege_escalation"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[],"cvss":{"score":7.8,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:L/AC:L/PR:L/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\nublk: clear VM_MAYWRITE on read-only ublk char device mmap\n\nublk_ch_mmap() rejects mmap requests with VM_WRITE set, but never\nclears VM_MAYWRITE on the resulting read-only mapping. This allows\na userspace daemon to mmap the per-queue command buffer PROT_READ,\nthen upgrade it to PROT_WRITE via mprotect(), since VM_MAYWRITE was\nnever cleared.\n\nThe command buffer holds struct ublksrv_io_desc entries that are\nkernel-written ABI; a writable mapping lets an unprivileged daemon\nprocess corrupt fields such as addr, op_flags, nr_sectors, and\nstart_sector.\n\nSame bug class as the drm/panthor and drm/vc4 VM_MAYWRITE fixes, and\nthe 2026-08-13 ptp/vmclock fix (a5edadbae57e).\n\nVerified via mprotect() PoC: before the fix, a PROT_READ mapping can\nbe upgraded to PROT_READ|PROT_WRITE and a write into the command\nbuffer corrupts io_desc fields (confirmed under KASAN). After the\nfix, mprotect() returns -EACCES.","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":"ublk: clear VM_MAYWRITE on read-only ublk char device mmap","id":"CVE-2026-89793","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"privilege_escalation","year":"2026"},"n_packages":0,"n_references":5,"next":{"headline":"ksmbd: zero pipe read compound padding","id":"CVE-2026-89794"},"packages":[],"prev":{"headline":"ksmbd: prevent out-of-bounds reads in share config responses","id":"CVE-2026-89792"},"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":"An unprivileged daemon can corrupt kernel-written I/O descriptors by upgrading a read-only mmap to writable, potentially leading to privilege escalation or code execution.","url":"https://insights.sbomify.com/CVE-2026-89793/"}