{"id":"CVE-2026-98085","state":"PUBLISHED","title":"bpf: backtrack_insn(): Handle ld_{abs,ind} subprog exit edge","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: backtrack_insn(): Handle ld_{abs,ind} subprog exit edge\n\nNicholas Carlini reported a bug in precision backtracking mechanism\nfor BPF_LD | BPF_{IND,ABS} instructions. These instructions are\nmodelled as two branches:\n- fallthrough;\n- implicit exit from current subprogram.\n\nThe implicit exit case was not handled by the backtrack_insn()\nfunction. When backtracking such a path backtrack_insn() did not\ncall bt_subprog_enter(), which meant that backtracking continued\nmanipulating precision marks in a caller frame, while looking at\ninstructions in a callee frame.\n\nThis lead to segmentation faults during verification (see the\nselftest), or unsound state pruning.","publishedAt":"2026-09-25T10:24:20.485Z","updatedAt":"2026-10-21T12:54:27.055Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"37ad2bb11e9de92cb7b94548705eeedd87f7d392","status":"affected","lessThan":"19cca7c36055906b3cff3e297618ee8a50cde25d","versionType":"git"},{"version":"8674e2db06cff6b50f2216eed9a761d15425bb34","status":"affected","lessThan":"12c064bcfa56e3631be9f5336ee113b7f849959a","versionType":"git"},{"version":"ce01a4e5cfac7adbe0be565f90cd32ecbb2f8337","status":"affected","lessThan":"a0cd9e22f8faed30a8da8be357c51bd8b3074ee9","versionType":"git"},{"version":"ee861486e377edc55361c08dcbceab3f6b6577bd","status":"affected","lessThan":"671b7b9a660ef15b25faa3df161205b9dc8d1eb2","versionType":"git"},{"version":"ee861486e377edc55361c08dcbceab3f6b6577bd","status":"affected","lessThan":"387b1baefbb776e3f48dc2261e77a49213f470f7","versionType":"git"},{"version":"928d354ae3557e8f755a227e67be88034eb3cd7f","status":"affected","versionType":"git"},{"version":"8a800497d9f6c2ec9c2c1ba7b71d0ac2ea7f7bbe","status":"affected","versionType":"git"},{"version":"de1055e7f9e67af32b1f3376066272b04e5223c0","status":"affected","versionType":"git"},{"version":"d846d83bdacbd8f14fc45c63b8c1d22608452e1c","status":"affected","versionType":"git"},{"version":"6.6.148","status":"affected","lessThan":"6.6.160","versionType":"semver"},{"version":"6.12.101","status":"affected","lessThan":"6.12.114","versionType":"semver"},{"version":"6.18.42","status":"affected","lessThan":"6.18.57","versionType":"semver"},{"version":"5.10.265","status":"affected","lessThan":"5.11","versionType":"semver"},{"version":"5.15.216","status":"affected","lessThan":"5.16","versionType":"semver"},{"version":"6.1.183","status":"affected","lessThan":"6.2","versionType":"semver"},{"version":"7.0.10","status":"affected","lessThan":"7.1","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/backtrack.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"7.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"7.1","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.114","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.7","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/backtrack.c"]}],"references":["https://git.kernel.org/stable/c/19cca7c36055906b3cff3e297618ee8a50cde25d","https://git.kernel.org/stable/c/12c064bcfa56e3631be9f5336ee113b7f849959a","https://git.kernel.org/stable/c/a0cd9e22f8faed30a8da8be357c51bd8b3074ee9","https://git.kernel.org/stable/c/671b7b9a660ef15b25faa3df161205b9dc8d1eb2","https://git.kernel.org/stable/c/387b1baefbb776e3f48dc2261e77a49213f470f7"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:43.249Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/98xxx/CVE-2026-98085.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98085","state":"PUBLISHED","datePublished":"2026-09-25T10:24:20.485Z","dateUpdated":"2026-10-21T12:54:27.055Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:19:56.075Z"},"containers":{"cna":{"title":"bpf: backtrack_insn(): Handle ld_{abs,ind} subprog exit edge","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: backtrack_insn(): Handle ld_{abs,ind} subprog exit edge\n\nNicholas Carlini reported a bug in precision backtracking mechanism\nfor BPF_LD | BPF_{IND,ABS} instructions. These instructions are\nmodelled as two branches:\n- fallthrough;\n- implicit exit from current subprogram.\n\nThe implicit exit case was not handled by the backtrack_insn()\nfunction. When backtracking such a path backtrack_insn() did not\ncall bt_subprog_enter(), which meant that backtracking continued\nmanipulating precision marks in a caller frame, while looking at\ninstructions in a callee frame.\n\nThis lead to segmentation faults during verification (see the\nselftest), or unsound state pruning."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"37ad2bb11e9de92cb7b94548705eeedd87f7d392","status":"affected","lessThan":"19cca7c36055906b3cff3e297618ee8a50cde25d","versionType":"git"},{"version":"8674e2db06cff6b50f2216eed9a761d15425bb34","status":"affected","lessThan":"12c064bcfa56e3631be9f5336ee113b7f849959a","versionType":"git"},{"version":"ce01a4e5cfac7adbe0be565f90cd32ecbb2f8337","status":"affected","lessThan":"a0cd9e22f8faed30a8da8be357c51bd8b3074ee9","versionType":"git"},{"version":"ee861486e377edc55361c08dcbceab3f6b6577bd","status":"affected","lessThan":"671b7b9a660ef15b25faa3df161205b9dc8d1eb2","versionType":"git"},{"version":"ee861486e377edc55361c08dcbceab3f6b6577bd","status":"affected","lessThan":"387b1baefbb776e3f48dc2261e77a49213f470f7","versionType":"git"},{"version":"928d354ae3557e8f755a227e67be88034eb3cd7f","status":"affected","versionType":"git"},{"version":"8a800497d9f6c2ec9c2c1ba7b71d0ac2ea7f7bbe","status":"affected","versionType":"git"},{"version":"de1055e7f9e67af32b1f3376066272b04e5223c0","status":"affected","versionType":"git"},{"version":"d846d83bdacbd8f14fc45c63b8c1d22608452e1c","status":"affected","versionType":"git"},{"version":"6.6.148","status":"affected","lessThan":"6.6.160","versionType":"semver"},{"version":"6.12.101","status":"affected","lessThan":"6.12.114","versionType":"semver"},{"version":"6.18.42","status":"affected","lessThan":"6.18.57","versionType":"semver"},{"version":"5.10.265","status":"affected","lessThan":"5.11","versionType":"semver"},{"version":"5.15.216","status":"affected","lessThan":"5.16","versionType":"semver"},{"version":"6.1.183","status":"affected","lessThan":"6.2","versionType":"semver"},{"version":"7.0.10","status":"affected","lessThan":"7.1","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/backtrack.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"7.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"7.1","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.114","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.7","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/bpf/backtrack.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/19cca7c36055906b3cff3e297618ee8a50cde25d"},{"url":"https://git.kernel.org/stable/c/12c064bcfa56e3631be9f5336ee113b7f849959a"},{"url":"https://git.kernel.org/stable/c/a0cd9e22f8faed30a8da8be357c51bd8b3074ee9"},{"url":"https://git.kernel.org/stable/c/671b7b9a660ef15b25faa3df161205b9dc8d1eb2"},{"url":"https://git.kernel.org/stable/c/387b1baefbb776e3f48dc2261e77a49213f470f7"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-21T12:54:27.055Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.148","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12.101","versionEndExcluding":"6.12.114"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.18.42","versionEndExcluding":"6.18.57"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.1","versionEndExcluding":"7.2.7"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.1","versionEndExcluding":"7.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10.265"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15.216"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1.183"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.0.10"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}