{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2026-99186 in the wild and no public exploit code.","fix":"Upgrade to a fixed version.","what":"CVE-2026-99186 is a vulnerability in Linux, published on 28 Oct 2026."},"fix_prompt":"Check this codebase for CVE-2026-99186 and fix it if it is affected.\n\nWhat it is: CVE-2026-99186 is a vulnerability in Linux, published on 28 Oct 2026. \nExploitation: There is no known exploitation of CVE-2026-99186 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-2026-99186/ (Markdown: https://insights.sbomify.com/CVE-2026-99186/index.md)","id":"CVE-2026-99186","markdown":"https://insights.sbomify.com/CVE-2026-99186/index.md","name":"CVE-2026-99186","record":{"aliases":["DEBIAN-CVE-2026-99186","GHSA-252w-9m2h-vq2g","UBUNTU-CVE-2026-99186"],"analysis":null,"analysis_generated_by":null,"assigner":"Linux","cpe":[],"cvss":{"score":null,"severity":null,"source":null,"vector":null,"version":null},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nx86/insn-eval: Fix shadowed segment index in get_seg_reg_override_idx()\n\nCommit 45e1dccc0653 (\"x86/insn: Simplify for_each_insn_prefix()\") made\nfor_each_insn_prefix() declare its own loop counter named idx.\nget_seg_reg_override_idx() keeps its result in a local of the same name,\nso the assignments in the loop body now write the loop counter:\n\n - the function always returns INAT_SEG_REG_DEFAULT, so FS and GS\n   overrides are ignored;\n\n - a CS override sets the counter to INAT_SEG_REG_CS (2), the increment\n   makes it 3, and prefixes.bytes[3] holds the last prefix, 0x2e again,\n   so the loop never terminates.\n\nThe UMIP emulation reaches this from the #GP handler for user space: an\nSGDT, SIDT or SMSW with a memory operand and a CS prefix leaves the task\nspinning in the kernel, never returning to user space, with a SIGKILL\nthat is never delivered.  Any user can thus tie up CPUs until reboot.\nWith an FS or GS prefix, the emulated result is written to the wrong\naddress.\n\nRename the internal macro iterator variable.\n\n[ Lukas' original patch renamed the use site, I changed it to rename the\n  iterator in the macro instead, but left Lukas' commit message and\n  authorship   - Linus ]","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":"x86/insn-eval: Fix shadowed segment index in get_seg_reg_override_idx()","id":"CVE-2026-99186","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":null,"year":"2026"},"n_packages":0,"n_references":2,"next":{"headline":"perf: Fix perf_pmu_migrate_context() leaving events behind","id":"CVE-2026-99187"},"packages":[],"prev":{"headline":"firewire: core: fix race condition in split transaction handling","id":"CVE-2026-99185"},"products":["Linux"],"published":"2026-10-28","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-10-28","vendors":["Linux"]},"summary":null,"url":"https://insights.sbomify.com/CVE-2026-99186/"}