{"id":"CVE-2026-98132","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: don't downgrade half-dead scalar zero spills to STACK_ZERO\n\nstates.c:__clean_func_state() can downgrade scalar zero spill to\nSTACK_ZERO in the following case:\n\n  *…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: don't downgrade half-dead scalar zero spills to STACK_ZERO\n\nstates.c:__clean_func_state() can downgrade scalar zero spill to\nSTACK_ZERO in the following case:\n\n  *…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= be23266b4a08540aa43d8503a2ea10247c8daebe < 436fa689630b741a77ef8c4a6f426479affd5bac","Linux >= be23266b4a08540aa43d8503a2ea10247c8daebe < 2f3536bff8823d3c5fdbbe15e17bfca696cc2b2e","Linux 7.1"],"published":"2026-09-25","updated":"2026-09-25","sourceUpdated":"2026-09-25T11:17:44.603","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-98132","references":[{"url":"https://git.kernel.org/stable/c/2f3536bff8823d3c5fdbbe15e17bfca696cc2b2e","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/436fa689630b741a77ef8c4a6f426479affd5bac","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-09-25T11:06:38.813Z","slug":"CVE-2026-98132","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nbpf: don't downgrade half-dead scalar zero spills to STACK_ZERO\n\nstates.c:__clean_func_state() can downgrade scalar zero spill to\nSTACK_ZERO in the following case:\n\n  *(u64 *)(r10 - 8) = 0;\n  ... checkpoint ...\n  r1 = *(u32 *)(r10 - 4);\n  ... no reads from r10-8 ...\n\nHere 4 bytes at r10-8 are dead and verifier changes scalar spill to a\ncombination: 0000pppp (p stands for poison). Such a change breaks\nprecision propagation chains. All places that produce STACK_ZERO\nshould call bpf_mark_chain_precision() for the zero source.\n\nThis patch fixes the bug in a simplest way possible:\navoids converting stack spills of zero to STACK_ZERO.\nTwo smarter approaches are possible:\n- do bpf_mark_chain_precision() from __clean_func_state()\n- check slot liveness information in check_stack_write_fixed_off()\n\nI investigated both and the changes required are a bit tricky,\nhence go with a simple fix for the time being.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}