CVE-2026-90392 (GCVE-0-2026-90392)
Vulnerability from cvelistv5
Published
2026-09-17 16:09
Modified
2026-10-30 12:35
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: bpf: Fix potential UAF when reading bpf link info In bpf_link_show_fdinfo and bpf_link_get_info_by_fd, link->prog is accessed without holding any locks. If the prog is concurrently replaced via bpf_link_update, the old prog can be freed, leading to a potential UAF issue. Fix this by accessing link->prog under RCU protection to safely fetch the pointer and guarantee its lifetime while reading its fields.
References
Impacted products
Vendor Product Version
Linux Linux Version: 0c991ebc8c69d29b7fc44db17075c5aa5253e2ab
Version: 0c991ebc8c69d29b7fc44db17075c5aa5253e2ab
Version: 0c991ebc8c69d29b7fc44db17075c5aa5253e2ab
Version: 0c991ebc8c69d29b7fc44db17075c5aa5253e2ab
Version: 0c991ebc8c69d29b7fc44db17075c5aa5253e2ab
Version: 0c991ebc8c69d29b7fc44db17075c5aa5253e2ab
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/bpf/syscall.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "versionType": "git"
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              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/bpf/syscall.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.7"
            },
            {
              "lessThan": "5.7",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.191",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.6",
              "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": "6.1.191",
                  "versionStartIncluding": "5.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.157",
                  "versionStartIncluding": "5.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.110",
                  "versionStartIncluding": "5.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.52",
                  "versionStartIncluding": "5.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.6",
                  "versionStartIncluding": "5.7",
                  "vulnerable": true
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "5.7",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix potential UAF when reading bpf link info\n\nIn bpf_link_show_fdinfo and bpf_link_get_info_by_fd, link-\u003eprog is\naccessed without holding any locks. If the prog is concurrently replaced\nvia bpf_link_update, the old prog can be freed, leading to a potential\nUAF issue.\n\nFix this by accessing link-\u003eprog under RCU protection to safely fetch\nthe pointer and guarantee its lifetime while reading its fields."
        }
      ],
      "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 dangling link-\u003eprog is read from the local bpf(2) BPF_OBJ_GET_INFO_BY_FD command (bpf_obj_get_info_by_fd()-\u003ebpf_link_get_info_by_fd()) or from bpf_link_show_fdinfo() when reading /proc/self/fdinfo on a bpf_link fd; neither path takes the malformed state from a network protocol.\nAC:L - The attacker owns both sides: one thread issues BPF_LINK_UPDATE so link_update() runs cgroup_bpf_replace()/tcx_link_update()/sock_map_link_update_prog() which xchg(\u0026link-\u003eprog) and bpf_prog_put() the old program, while another thread they control races bpf_link_get_info_by_fd() or bpf_link_show_fdinfo(), which sleeps in seq_printf after capturing the pointer.\nPR:L - Creating a replaceable link requires bpf_prog_load() of a type whose ops implement update_prog (CGROUP_SKB, SCHED_CLS, SK_SKB, XDP, FLOW_DISSECTOR) plus BPF_LINK_CREATE; those paths require bpf_token_capable(CAP_BPF) and usually CAP_NET_ADMIN (CGROUP_SKB attach also checks it in bpf_prog_attach_check_attach_type), which a BPF token delegates into a user namespace.\nUI:N - The attacker loads two programs, BPF_LINK_CREATE the first as a cgroup/tcx/sockmap/xdp/netns link, closes the old program fd so the link holds the last ref, then races BPF_LINK_UPDATE against BPF_OBJ_GET_INFO_BY_FD or fdinfo in their own process; no other user action is required.\nS:U - The use-after-free is of the replaced bpf_prog inside bpf_link_get_info_by_fd()/bpf_link_show_fdinfo() on the host kernel; impact is local kernel memory corruption and privilege escalation, not a VM, IOMMU, or other authority-boundary cross.\nC:H - After the concurrent bpf_prog_put(), bpf_link_get_info_by_fd() reads prog-\u003eaux-\u003eid and bpf_link_show_fdinfo() copies prog-\u003etag then aux-\u003eid from the freed bpf_prog; __bpf_prog_free() kfree()s the kmalloc bpf_prog_aux, so reclaiming that object turns the dangling aux pointer into an arbitrary kernel read.\nI:H - The same bpf_prog/bpf_prog_aux use-after-free after cgroup_bpf_replace() (or tcx/sockmap/xdp/netns update_prog) lets the attacker spray the freed kmalloc aux and vmalloc prog; kernel heap UAF of those objects yields write and control-flow hijack primitives.\nA:H - bpf_link_get_info_by_fd() and bpf_link_show_fdinfo() dereference the freed bpf_prog and prog-\u003eaux after BPF_LINK_UPDATE drops the last ref via bpf_prog_put(); a recycled or poisoned aux pointer causes a kernel oops."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-30T12:35:28.141Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/4c8432a332d4a24dc2742f56062a53d8fad36f53"
        },
        {
          "url": "https://git.kernel.org/stable/c/a5c936ac904767fc1d943d40b0308bcb2ae2509b"
        },
        {
          "url": "https://git.kernel.org/stable/c/d7d7208e2603b45724b684f4df73904fb347741e"
        },
        {
          "url": "https://git.kernel.org/stable/c/85cf991c881e7198be32be05a9daa2625390c8b3"
        },
        {
          "url": "https://git.kernel.org/stable/c/79347e42cfbc9e78872922e8f08a70609c9af82f"
        },
        {
          "url": "https://git.kernel.org/stable/c/863f3ddd0b8ac65abfb50d3be0869268ac0e277b"
        }
      ],
      "title": "bpf: Fix potential UAF when reading bpf link info",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-90392",
    "datePublished": "2026-09-17T16:09:25.738Z",
    "dateReserved": "2026-09-11T19:38:34.810Z",
    "dateUpdated": "2026-10-30T12:35:28.141Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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