{
  "threat_severity" : "Moderate",
  "public_date" : "2026-04-22T00:00:00Z",
  "bugzilla" : {
    "description" : "kernel: bpf: Fix exception exit lock checking for subprogs",
    "id" : "2460702",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2460702"
  },
  "cvss3" : {
    "cvss3_base_score" : "5.5",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
    "status" : "draft"
  },
  "cwe" : "CWE-772",
  "details" : [ "In the Linux kernel, the following vulnerability has been resolved:\nbpf: Fix exception exit lock checking for subprogs\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.\nAt runtime bpf_throw() unwinds the stack via ORC without releasing any\nuser-acquired locks, which may cause various issues as the result.\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.\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.\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[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/kernel/bpf/verifier.c?h=v7.0-rc4#n21098", "A flaw was found in the Linux kernel's Berkeley Packet Filter (BPF) subsystem. When an exception occurs during the execution of a BPF subprogram, the system may fail to release user-acquired locks. This oversight can lead to resource leaks and system instability, potentially resulting in a Denial of Service (DoS) condition." ],
  "statement" : "Verifier now enforces lock leak checks on `bpf_throw()` exception exits from subprograms, matching real unwind behavior. Red Hat notes impact is confined to verified BPF programs that use exceptions with RCU/preempt/irq state; typical production programs should fail verification until fixed. Ship via kernel errata.",
  "package_state" : [ {
    "product_name" : "Red Hat Enterprise Linux 10",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:10"
  }, {
    "product_name" : "Red Hat Enterprise Linux 6",
    "fix_state" : "Not affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:6"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Fix deferred",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2026-31526\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-31526\nhttps://lore.kernel.org/linux-cve-announce/2026042213-CVE-2026-31526-9771@gregkh/T" ],
  "name" : "CVE-2026-31526",
  "csaw" : false
}