CVE-2026-98220: Software Security Vulnerability Vulnerability

UNKNOWN
Advisory Identifier: GHSA-h6hx-xpp5-6vc3
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Advisory Summary

CVE-2026-98220 is a security vulnerability vulnerability (General Security Weakness) affecting Software libraries in the Maven ecosystem. Remediation is available in the latest vendor maintenance releases.

CVE-2026-98220 at a Glance

CVE Identifier CVE-2026-98220
GHSA Identifier GHSA-h6hx-xpp5-6vc3
Severity N/A
CVSS v3.1 Base Score N/A
CWE Classification General Security Weakness
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

How to Fix CVE-2026-98220

To remediate this vulnerability, upgrade all affected Software dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-98220, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree

Analyze the terminal output to locate any version of Software in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The mvn dependency:tree command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under General Security Weakness. In Software, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

In the Linux kernel, the following vulnerability has been resolved: sched_ext: Fix NULL sched deref in kfunc sub-sched error paths When the root scheduler has sub-scheds attached, the COMPAT kfunc wrappers scx_bpf_select_cpu_and() and scx_bpf_dsq_insert_vtime() refuse the call and report to @p's scheduler: scx_error(scx_task_sched(p), "... must be used"); The wrappers are reachable with tasks that have no scheduler. scx_bpf_select_cpu_and() is in the select_cpu kfunc group, which scx_kfunc_context_filter() opens to BPF_PROG_TYPE_SYSCALL programs; scx_bpf_dsq_insert_vtime() is in the enqueue_dispatch group, which ops.enqueue() and ops.dispatch() may call with any KF_RCU task -- the group has no kf_tasks validation, and scx_dsq_insert_preamble() checks task ownership with scx_task_on_sched() precisely because @p may be an arbitrary task. scx_task_sched(p) is p->scx.sched, which is NULL for tasks past sched_ext_dead() -- which clears it via scx_disable_and_exit_task() on exit -- and for idle tasks, which the enable paths skip as they are never scheduled through SCX. It is also an rcu_dereference_protected() that expects @p's pi_lock or rq lock, which neither wrapper holds. Passing NULL to scx_error() reaches scx_vexit(), which dereferences sch->exit_info, oopsing the kernel. One concrete trigger exercised while developing the fix: a BPF_PROG_TYPE_SYSCALL program calling the select_cpu_and wrapper on an exited-but-not-reaped task while a sub-scheduler was attached (its pid stays findable while the zombie is unreaped; faulting instruction is the scx_vexit() prologue "mov r15,[rdi+0x398]" with RDI=NULL and 0x398 the offset of sch->exit_info): sched_ext: BPF scheduler "kfunc_subsched_null" enabled sched_ext: BPF sub-scheduler "kfunc_subsched_null" enabled sched_ext: Unassociated program run_select_cpu_ (id 76) BUG: kernel NULL pointer dereference, address: 0000000000000398 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page Oops: Oops: 0000 [#1] SMP NOPTI CPU: 7 UID: 0 PID: 8201 Comm: kfunc_test_runn Tainted: G W RIP: 0010:scx_vexit+0x25/0xa0 Code: ... <4c> 8b bf 98 03 00 00 ... CR2: 0000000000000398 Call Trace: <TASK> __scx_exit+0x4f/0x70 scx_bpf_select_cpu_and+0xab/0xb0 bpf_prog_430ed61a7b66e03a_run_select_cpu_and+0x9c/0xe7 ? __x64_sys_bpf+0x2c/0x40 bpf_prog_test_run_syscall+0x130/0x2f0 __sys_bpf+0x930/0x10d0 ? __x64_sys_bpf+0x2c/0x40 __x64_sys_bpf+0x2c/0x40 do_syscall_64+0xbc/0x460 entry_SYSCALL_64_after_hwframe+0x76/0x7e </TASK> Read @p's scheduler under RCU instead, which the wrappers can do from their guard(rcu)(): fault it when it can be determined, and when it can't be determined -- @p is a task past sched_ext_dead() or an idle task -- there is nothing obviously wrong to report, so just refuse the call as before without faulting any scheduler. These COMPAT wrappers are scheduled for eventual removal once the deprecation grace period elapses, but until then -- and regardless of their removal timeline -- they must not oops the kernel on a task they are handed.

References

NVD — CVE-2026-98220 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-98220
git.kernel.org/stable/c/0a85182723... WEB
https://git.kernel.org/stable/c/0a85182723b65ad8bee8131bc38fcf0347d6679b
git.kernel.org/stable/c/589f0945bf... WEB
https://git.kernel.org/stable/c/589f0945bf3ebf0790fd51e28c7f0d04ed3d8b78

Frequently Asked Questions

What is CVE-2026-98220?
CVE-2026-98220 is a security vulnerability in Software classified as a security vulnerability vulnerability under General Security Weakness.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-98220?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What CWE is associated with CVE-2026-98220?
CVE-2026-98220 is classified under General Security Weakness.
How can I check Maven dependencies for CVE-2026-98220?
Run the dependency tree command: 'mvn dependency:tree'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-h6hx-xpp5-6vc3",
  "modified" : "2026-10-06T09:31:31Z",
  "published" : "2026-10-06T09:31:31Z",
  "aliases" : [ "CVE-2026-98220" ],
  "details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Fix NULL sched deref in kfunc sub-sched error paths\n\nWhen the root scheduler has sub-scheds attached, the COMPAT kfunc\nwrappers scx_bpf_select_cpu_and() and scx_bpf_dsq_insert_vtime() refuse\nthe call and report to @p's scheduler:\n\n\tscx_error(scx_task_sched(p), \"... must be used\");\n\nThe wrappers are reachable with tasks that have no scheduler.\nscx_bpf_select_cpu_and() is in the select_cpu kfunc group, which\nscx_kfunc_context_filter() opens to BPF_PROG_TYPE_SYSCALL programs;\nscx_bpf_dsq_insert_vtime() is in the enqueue_dispatch group, which\nops.enqueue() and ops.dispatch() may call with any KF_RCU task -- the\ngroup has no kf_tasks validation, and scx_dsq_insert_preamble() checks\ntask ownership with scx_task_on_sched() precisely because @p may be an\narbitrary task.\n\nscx_task_sched(p) is p->scx.sched, which is NULL for tasks past\nsched_ext_dead() -- which clears it via scx_disable_and_exit_task() on\nexit -- and for idle tasks, which the enable paths skip as they are\nnever scheduled through SCX. It is also an rcu_dereference_protected()\nthat expects @p's pi_lock or rq lock, which neither wrapper holds.\nPassing NULL to scx_error() reaches scx_vexit(), which dereferences\nsch->exit_info, oopsing the kernel.\n\nOne concrete trigger exercised while developing the fix: a\nBPF_PROG_TYPE_SYSCALL program calling the select_cpu_and wrapper on an\nexited-but-not-reaped task while a sub-scheduler was attached (its pid\nstays findable while the zombie is unreaped; faulting instruction is\nthe scx_vexit() prologue \"mov r15,[rdi+0x398]\" with RDI=NULL and 0x398\nthe offset of sch->exit_info):\n\n  sched_ext: BPF scheduler \"kfunc_subsched_null\" enabled\n  sched_ext: BPF sub-scheduler \"kfunc_subsched_null\" enabled\n  sched_ext: Unassociated program run_select_cpu_ (id 76)\n  BUG: kernel NULL pointer dereference, address: 0000000000000398\n  #PF: supervisor read access in kernel mode\n  #PF: error_code(0x0000) - not-present page\n  Oops: Oops: 0000 [#1] SMP NOPTI\n  CPU: 7 UID: 0 PID: 8201 Comm: kfunc_test_runn Tainted: G W\n  RIP: 0010:scx_vexit+0x25/0xa0\n  Code: ... <4c> 8b bf 98 03 00 00 ...\n  CR2: 0000000000000398\n  Call Trace:\n   <TASK>\n   __scx_exit+0x4f/0x70\n   scx_bpf_select_cpu_and+0xab/0xb0\n   bpf_prog_430ed61a7b66e03a_run_select_cpu_and+0x9c/0xe7\n   ? __x64_sys_bpf+0x2c/0x40\n   bpf_prog_test_run_syscall+0x130/0x2f0\n   __sys_bpf+0x930/0x10d0\n   ? __x64_sys_bpf+0x2c/0x40\n   __x64_sys_bpf+0x2c/0x40\n   do_syscall_64+0xbc/0x460\n   entry_SYSCALL_64_after_hwframe+0x76/0x7e\n   </TASK>\n\nRead @p's scheduler under RCU instead, which the wrappers can do from\ntheir guard(rcu)(): fault it when it can be determined, and when it\ncan't be determined -- @p is a task past sched_ext_dead() or an idle\ntask -- there is nothing obviously wrong to report, so just refuse the\ncall as before without faulting any scheduler.\n\nThese COMPAT wrappers are scheduled for eventual removal once the\ndeprecation grace period elapses, but until then -- and regardless of\ntheir removal timeline -- they must not oops the kernel on a task they\nare handed.",
  "severity" : [ ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-98220"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/0a85182723b65ad8bee8131bc38fcf0347d6679b"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/589f0945bf3ebf0790fd51e28c7f0d04ed3d8b78"
  } ],
  "database_specific" : {
    "cwe_ids" : [ ],
    "severity" : null,
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-10-06T09:18:08Z"
  }
}