CVE-2026-89906 (GCVE-0-2026-89906)
Vulnerability from cvelistv5
Published
2026-09-16 10:32
Modified
2026-10-21 12:49
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: LoongArch: BPF: Refactor jump offset calculation in tail call The old macro-based jmp_offset calculation derives the jump distance from a stale prior-pass code stride, which can lead to wrong branch offsets and soft lockups under extra JIT passes. Fix this by calculating the offset directly on the absolute target: "ctx->offset[insn + 1] - ctx->idx". To avoid a false 16-bit range check abort during size estimation, add a "ctx->image == NULL" guard to inject a safe dummy offset.
References
Impacted products
Vendor Product Version
Linux Linux Version: 17c010fe45def335fe03a0718935416b04c7f349
Version: f83d469e16bb1f75991ca67c56786fb2aaa42bea
Version: cd39d9e6b7e4c58fa77783e7aedf7ada51d02ea3
Version: cd39d9e6b7e4c58fa77783e7aedf7ada51d02ea3
Version: cd39d9e6b7e4c58fa77783e7aedf7ada51d02ea3
Version: 1a782fa32e644aa9fbae6c8488f3e61221ac96e1
Version: f2b5e50cc04d7a049b385bc1c93b9cbf5f10c94f
Version: 9262e3e04621558e875eb5afb5e726b648cd5949
Version: 6.6.103   ≤
Version: 6.12.43   ≤
Version: 6.1.149   ≤
Version: 6.15.11   ≤
Version: 6.16.2   ≤
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/loongarch/net/bpf_jit.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "lessThan": "50fbc294e4e96246d60cd66f98acf043a362e3a0",
              "status": "affected",
              "version": "17c010fe45def335fe03a0718935416b04c7f349",
              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "f83d469e16bb1f75991ca67c56786fb2aaa42bea",
              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "cd39d9e6b7e4c58fa77783e7aedf7ada51d02ea3",
              "versionType": "git"
            },
            {
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              "status": "affected",
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            {
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            {
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              "versionType": "git"
            },
            {
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            {
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              "version": "9262e3e04621558e875eb5afb5e726b648cd5949",
              "versionType": "git"
            },
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              "status": "affected",
              "version": "6.6.103",
              "versionType": "semver"
            },
            {
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              "status": "affected",
              "version": "6.12.43",
              "versionType": "semver"
            },
            {
              "lessThan": "6.2",
              "status": "affected",
              "version": "6.1.149",
              "versionType": "semver"
            },
            {
              "lessThan": "6.16",
              "status": "affected",
              "version": "6.15.11",
              "versionType": "semver"
            },
            {
              "lessThan": "6.17",
              "status": "affected",
              "version": "6.16.2",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/loongarch/net/bpf_jit.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.17"
            },
            {
              "lessThan": "6.17",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.160",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.114",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.51",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.160",
                  "versionStartIncluding": "6.6.103",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.114",
                  "versionStartIncluding": "6.12.43",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.51",
                  "versionStartIncluding": "6.17",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.5",
                  "versionStartIncluding": "6.17",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "6.17",
                  "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": "6.15.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "6.16.2",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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-\u003eoffset[insn + 1] - ctx-\u003eidx\".\n\nTo avoid a false 16-bit range check abort during size estimation, add\na \"ctx-\u003eimage == NULL\" guard to inject a safe dummy offset."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "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\u0027s 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-\u003eptrs[] 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-\u003ebpf_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."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-21T12:49:06.262Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/50fbc294e4e96246d60cd66f98acf043a362e3a0"
        },
        {
          "url": "https://git.kernel.org/stable/c/89819868cde78cb2f748533785a46a3430873f20"
        },
        {
          "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"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89906",
    "datePublished": "2026-09-16T10:32:05.157Z",
    "dateReserved": "2026-09-11T19:38:34.774Z",
    "dateUpdated": "2026-10-21T12:49:06.262Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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