{"id":"CVE-2026-72111","title":"bpf: Reset register bounds before narrowing retval range in check_mem_access()","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Reset register bounds before narrowing retval range in check_mem_access()\n\nWhen the BPF verifier processes a context load of an LSM hook return\nvalue, it calls __m…","severity":"high","cvss":8.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 5d99e198be279045e6ecefe220f5c52f8ce9bfd5 < bde92f65042ec14389782dd223f706bf6b59ce5d","Linux >= 5d99e198be279045e6ecefe220f5c52f8ce9bfd5 < 0993dc5fc619c0b25ab1310cb11d65e78351c0fe","Linux >= 5d99e198be279045e6ecefe220f5c52f8ce9bfd5 < 5a55f9aecc08990940e70f0c7048a80850c5a16a","Linux >= 5d99e198be279045e6ecefe220f5c52f8ce9bfd5 < 5e0b273e0a62cc04ec338c7b502797c66c2ed42a","Linux 1050727d83e70449991c29dd1cf29fe936a63da3","Linux 27ca3e20fe80be85a92b10064dfeb56cb2564b1c","Linux >= 6.10.13 < 6.11","Linux >= 6.11.2 < 6.12","Linux 6.12"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-16T18:41:38.213605Z"},"published":"2026-08-15","updated":"2026-10-16","sourceUpdated":"2026-10-16T18:44:56.296Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-72111","references":[{"url":"https://git.kernel.org/stable/c/bde92f65042ec14389782dd223f706bf6b59ce5d"},{"url":"https://git.kernel.org/stable/c/0993dc5fc619c0b25ab1310cb11d65e78351c0fe"},{"url":"https://git.kernel.org/stable/c/5a55f9aecc08990940e70f0c7048a80850c5a16a"},{"url":"https://git.kernel.org/stable/c/5e0b273e0a62cc04ec338c7b502797c66c2ed42a"}],"tags":["cve.org"],"epss":0.00176,"epssPercentile":0.06695,"ingestedAt":"2026-10-16T19:46:24.432Z","slug":"CVE-2026-72111","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Reset register bounds before narrowing retval range in check_mem_access()\n\nWhen the BPF verifier processes a context load of an LSM hook return\nvalue, it calls __mark_reg_s32_range() to narrow the register to the\nhook's valid range. However, __mark_reg_s32_range() intersects the new\nrange with the register's existing bounds using max_t()/min_t() rather\nthan replacing them.\n\nIf the destination register carries stale bounds from a prior instruction\n(e.g. BPF_MOV64_IMM), the intersection can produce a range narrower than\nreality. The verifier then believes it knows the register's exact value,\nwhile at runtime the actual hook return value is loaded, creating a\nverifier/runtime mismatch that can be used to bypass BPF memory safety\nchecks.\n\nThe else branch already calls mark_reg_unknown() to reset register state\nbefore any narrowing. Apply the same reset in the is_retval path so\nstale bounds are cleared before __mark_reg_s32_range() intersects.\n\n## Affected\n\n- `Linux >= 5d99e198be279045e6ecefe220f5c52f8ce9bfd5 < bde92f65042ec14389782dd223f706bf6b59ce5d`\n- `Linux >= 5d99e198be279045e6ecefe220f5c52f8ce9bfd5 < 0993dc5fc619c0b25ab1310cb11d65e78351c0fe`\n- `Linux >= 5d99e198be279045e6ecefe220f5c52f8ce9bfd5 < 5a55f9aecc08990940e70f0c7048a80850c5a16a`\n- `Linux >= 5d99e198be279045e6ecefe220f5c52f8ce9bfd5 < 5e0b273e0a62cc04ec338c7b502797c66c2ed42a`\n- `Linux 1050727d83e70449991c29dd1cf29fe936a63da3`\n- `Linux 27ca3e20fe80be85a92b10064dfeb56cb2564b1c`\n- `Linux >= 6.10.13 < 6.11`\n- `Linux >= 6.11.2 < 6.12`\n- `Linux 6.12`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":48,"depthScoreParts":{"impact":48.4,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}