Vulnerability in Kernel (CVE-2026-31733)

Summary

Vulnerability in Kernel (CVE-2026-31733). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 6.12.82, 6.18.22, 6.19.12 or later.

Original description

The description as published by the source.

In the Linux kernel, the following vulnerability has been resolved:

sched_ext: Fix stale direct dispatch state in ddsp_dsq_id

@p->scx.ddsp_dsq_id can be left set (non-SCX_DSQ_INVALID) triggering a
spurious warning in mark_direct_dispatch() when the next wakeup's
ops.select_cpu() calls scx_bpf_dsq_insert(), such as:

WARNING: kernel/sched/ext.c:1273 at scx_dsq_insert_commit+0xcd/0x140

The root cause is that ddsp_dsq_id was only cleared in dispatch_enqueue(),
which is not reached in all paths that consume or cancel a direct dispatch
verdict.

Fix it by clearing it at the right places:

direct_dispatch(): cache the direct dispatch state in local variables
and clear it before dispatch_enqueue() on the synchronous path. For
the deferred path, the direct dispatch state must remain set until
process_ddsp_deferred_locals() consumes them.
process_ddsp_deferred_locals(): cache the dispatch state in local
variables and clear it before calling dispatch_to_local_dsq(), which
may migrate the task to another rq.
do_enqueue_task(): clear the dispatch state on the enqueue path
(local/global/bypass fallbacks), where the direct dispatch verdict is
ignored.
dequeue_task_scx(): clear the dispatch state after dispatch_dequeue()
to handle both the deferred dispatch cancellation and the holding_cpu
race, covering all cases where a pending direct dispatch is
cancelled.
scx_disable_task(): clear the direct dispatch state when
transitioning a task…

Source: OSV.dev (Open Source Vulnerabilities) NVD OSV

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-31733 has been found in Kernel.
Risk of unauthorized operations or information disclosure.
What to do: upgrade Kernel to 6.12.82, 6.18.22, 6.19.12 or later.
If unsure, ask your IT team or search "Kernel CVE-2026-31733" on the vendor's site.

CVE-2026-31733 (Kernel)
Patched: 6.12.82, 6.18.22, 6.19.12 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (unclassified) exists in Kernel.

📍 Affected scope

Check the vendor advisory for the affected versions of Kernel.

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 6.12.82, 6.18.22, 6.19.12.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'Kernel' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

1
Identify exposure identify
```
grep -r 'Kernel' . | grep -v node_modules
```
リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で Kernel を grep し、稼働しているサービス・バージョンを把握する。
2
Apply patch patch
```
Upgrade Kernel to 6.12.82, 6.18.22, 6.19.12
```
ステージング環境で 6.12.82, 6.18.22, 6.19.12 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
3
Post-deployment verification verify
```
Confirm patched version is live in production
```
パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

Linux Kernel

[{"type":"ECOSYSTEM","events":[{"introduced":"6.12.0"},{"fixed":"6.12.82"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.22"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.12"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2026-31733 linux-lts Fixed in: 6.12.85-r0
Debian DEBIAN-CVE-2026-31733 linux Fixed in: 6.12.85-1
Ubuntu UBUNTU-CVE-2026-31733 linux-hwe-edge