{"id":"CVE-2026-72111","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-72111","generatedAt":"2026-10-28T03:26:15.244Z","title":"In the Linux kernel, the following vulnerability has been resolved: bpf: Reset register bounds before narrowing retval range in check_mem_access() When the BPF verifier processes a context load of an LSM hook return value, it calls…","description":"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 __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.","published":"2026-08-15T06:21:25.000Z","lastModified":"2026-10-16T19:17:09.000Z","status":"Received","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":{"version":"3.1","score":8.8,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H"},"cwe":[],"affected":[],"epss":{"score":0.00176,"percentile":0.07095,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.18%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/0993dc5fc619c0b25ab1310cb11d65e78351c0fe","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5a55f9aecc08990940e70f0c7048a80850c5a16a","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5e0b273e0a62cc04ec338c7b502797c66c2ed42a","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/bde92f65042ec14389782dd223f706bf6b59ce5d","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-72111","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}