{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-89906", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.774Z", "datePublished": "2026-09-16T10:32:05.157Z", "dateUpdated": "2026-10-19T08:54:38.965Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:54:38.965Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nLoongArch: BPF: Refactor jump offset calculation in tail call\n\nThe old macro-based jmp_offset calculation derives the jump distance\nfrom a stale prior-pass code stride, which can lead to wrong branch\noffsets and soft lockups under extra JIT passes.\n\nFix this by calculating the offset directly on the absolute target:\n\"ctx->offset[insn + 1] - ctx->idx\".\n\nTo avoid a false 16-bit range check abort during size estimation, add\na \"ctx->image == NULL\" guard to inject a safe dummy offset." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The bug is in the LoongArch eBPF JIT emit_bpf_tail_call() and is reached only by loading a program that uses bpf_tail_call via bpf(BPF_PROG_LOAD) on the local host. Kernel CNA guidance classifies BPF as a local attack vector.\nAC:L - The attacker fully controls the BPF bytecode, including bpf2bpf subprograms that force the extra JIT pass where the stale prior-pass stride is used. Wrong jmp_offset encodings are deterministic for a given program (the in-tree tailcall_bpf2bpf_1 case), with no race or layout outside attacker control.\nPR:L - BPF_MAP_TYPE_PROG_ARRAY is an unprivileged map type, bpf_tail_call_proto is returned before the CAP_BPF gate, and SOCKET_FILTER programs load without CAP_BPF where unprivileged BPF is enabled. Otherwise only CAP_BPF or a delegated BPF token in a user namespace is required, not init-namespace root.\nUI:N - The attacker loads the crafted program, attaches it to a socket they own or runs it with BPF_PROG_TEST_RUN, and triggers the miscompiled tail call themselves. No separate victim action is required.\nS:U - The wrong branches execute inside the host kernel's own JIT image and corrupt in-kernel control flow. That is standard kernel privilege-escalation impact, not a VM, IOMMU, or hypervisor boundary crossing.\nC:H - Miscomputed tail-call \"goto out\" branches can land inside the remaining sequence after the max_entries check, so an out-of-range index performs an OOB load of array->ptrs[] and treats the result as a function pointer, disclosing kernel memory. Mid-image jumps likewise execute attacker-shaped JIT loads at kernel privilege.\nI:H - The same OOB ptrs[] load is followed by an indirect jump through prog->bpf_func, hijacking kernel control flow. Branches that skip the NULL or tail-call-count checks, or that land mid-instruction, likewise yield a kernel-mode write and control-flow primitive.\nA:H - The fix and the prior incomplete tail-call offset patch document watchdog soft lockups from wrong, including backward, branches looping in kernel context. Any such hang, oops, or panic is Availability High." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "arch/loongarch/net/bpf_jit.c" ], "versions": [ { "version": "cd39d9e6b7e4c58fa77783e7aedf7ada51d02ea3", "lessThan": "882b8912b7e92341fdb115ba0e2e5142a28684ff", "status": "affected", "versionType": "git" }, { "version": "cd39d9e6b7e4c58fa77783e7aedf7ada51d02ea3", "lessThan": "96f44d493c280ea161569c43d7ed0f3b0815803a", "status": "affected", "versionType": "git" }, { "version": "cd39d9e6b7e4c58fa77783e7aedf7ada51d02ea3", "lessThan": "37d545d12f21c4d50612ecaebd7ae1e5bf91b2d8", "status": "affected", "versionType": "git" }, { "version": "1a782fa32e644aa9fbae6c8488f3e61221ac96e1", "status": "affected", "versionType": "git" }, { "version": "17c010fe45def335fe03a0718935416b04c7f349", "status": "affected", "versionType": "git" }, { "version": "f83d469e16bb1f75991ca67c56786fb2aaa42bea", "status": "affected", "versionType": "git" }, { "version": "f2b5e50cc04d7a049b385bc1c93b9cbf5f10c94f", "status": "affected", "versionType": "git" }, { "version": "9262e3e04621558e875eb5afb5e726b648cd5949", "status": "affected", "versionType": "git" }, { "version": "6.1.149", "lessThan": "6.2", "status": "affected", "versionType": "semver" }, { "version": "6.6.103", "lessThan": "6.7", "status": "affected", "versionType": "semver" }, { "version": "6.12.43", "lessThan": "6.13", "status": "affected", "versionType": "semver" }, { "version": "6.15.11", "lessThan": "6.16", "status": "affected", "versionType": "semver" }, { "version": "6.16.2", "lessThan": "6.17", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "arch/loongarch/net/bpf_jit.c" ], "versions": [ { "version": "6.17", "status": "affected" }, { "version": "0", "lessThan": "6.17", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.51", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.5", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.17", "versionEndExcluding": "6.18.51" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.17", "versionEndExcluding": "7.2.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.17", "versionEndExcluding": "7.3" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1.149" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6.103" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12.43" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.16.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/882b8912b7e92341fdb115ba0e2e5142a28684ff" }, { "url": "https://git.kernel.org/stable/c/96f44d493c280ea161569c43d7ed0f3b0815803a" }, { "url": "https://git.kernel.org/stable/c/37d545d12f21c4d50612ecaebd7ae1e5bf91b2d8" } ], "title": "LoongArch: BPF: Refactor jump offset calculation in tail call", "x_generator": { "engine": "bippy-1.2.0" } } } }