CVE-2026-31526 (GCVE-0-2026-31526)
Vulnerability from cvelistv5
Published
2026-04-22 13:54
Modified
2026-05-11 22:10
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix exception exit lock checking for subprogs process_bpf_exit_full() passes check_lock = !curframe to check_resource_leak(), which is false in cases when bpf_throw() is called from a static subprog. This makes check_resource_leak() to skip validation of active_rcu_locks, active_preempt_locks, and active_irq_id on exception exits from subprogs. At runtime bpf_throw() unwinds the stack via ORC without releasing any user-acquired locks, which may cause various issues as the result. Fix by setting check_lock = true for exception exits regardless of curframe, since exceptions bypass all intermediate frame cleanup. Update the error message prefix to "bpf_throw" for exception exits to distinguish them from normal BPF_EXIT. Fix reject_subprog_with_rcu_read_lock test which was previously passing for the wrong reason. Test program returned directly from the subprog call without closing the RCU section, so the error was triggered by the unclosed RCU lock on normal exit, not by bpf_throw. Update __msg annotations for affected tests to match the new "bpf_throw" error prefix. The spin_lock case is not affected because they are already checked [1] at the call site in do_check_insn() before bpf_throw can run. [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/kernel/bpf/verifier.c?h=v7.0-rc4#n21098
References
Impacted products
Vendor Product Version
Linux Linux Version: f18b03fabaa9b7c80e80b72a621f481f0d706ae0
Version: f18b03fabaa9b7c80e80b72a621f481f0d706ae0
Version: f18b03fabaa9b7c80e80b72a621f481f0d706ae0
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/bpf/verifier.c",
            "tools/testing/selftests/bpf/progs/exceptions_fail.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "c0281da1f2aa5c2fca3a05f79b86bea96591c358",
              "status": "affected",
              "version": "f18b03fabaa9b7c80e80b72a621f481f0d706ae0",
              "versionType": "git"
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        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
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            "tools/testing/selftests/bpf/progs/exceptions_fail.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.7"
            },
            {
              "lessThan": "6.7",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.21",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.21",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                },
                {
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                  "versionEndExcluding": "6.19.11",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0",
                  "versionStartIncluding": "6.7",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix exception exit lock checking for subprogs\n\nprocess_bpf_exit_full() passes check_lock = !curframe to\ncheck_resource_leak(), which is false in cases when bpf_throw() is\ncalled from a static subprog. This makes check_resource_leak() to skip\nvalidation of active_rcu_locks, active_preempt_locks, and\nactive_irq_id on exception exits from subprogs.\n\nAt runtime bpf_throw() unwinds the stack via ORC without releasing any\nuser-acquired locks, which may cause various issues as the result.\n\nFix by setting check_lock = true for exception exits regardless of\ncurframe, since exceptions bypass all intermediate frame\ncleanup. Update the error message prefix to \"bpf_throw\" for exception\nexits to distinguish them from normal BPF_EXIT.\n\nFix reject_subprog_with_rcu_read_lock test which was previously\npassing for the wrong reason. Test program returned directly from the\nsubprog call without closing the RCU section, so the error was\ntriggered by the unclosed RCU lock on normal exit, not by\nbpf_throw. Update __msg annotations for affected tests to match the\nnew \"bpf_throw\" error prefix.\n\nThe spin_lock case is not affected because they are already checked [1]\nat the call site in do_check_insn() before bpf_throw can run.\n\n[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/kernel/bpf/verifier.c?h=v7.0-rc4#n21098"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-11T22:10:30.204Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/c0281da1f2aa5c2fca3a05f79b86bea96591c358"
        },
        {
          "url": "https://git.kernel.org/stable/c/5a399f3117642494e35545f6ca397d3e177c1f9b"
        },
        {
          "url": "https://git.kernel.org/stable/c/6c2128505f61b504c79a20b89596feba61388112"
        }
      ],
      "title": "bpf: Fix exception exit lock checking for subprogs",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-31526",
    "datePublished": "2026-04-22T13:54:39.800Z",
    "dateReserved": "2026-03-09T15:48:24.111Z",
    "dateUpdated": "2026-05-11T22:10:30.204Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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