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CVE-2025-71066 high CVSS 7.8

Vulnerability in Kernel (CVE-2025-71066)

Summary

Vulnerability in Kernel (CVE-2025-71066). Successful exploitation can lead to full system takeover. Exploitable via ets_qdisc_dequeue. Mitigation: upgrade to 5.10.248, 5.15.198, 6.1.160, 6.6.120, 6.12.64, 6.18.3 or later.

Original description

The description as published by the source.

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

net/sched: ets: Always remove class from active list before deleting in ets_qdisc_change

zdi-disclosures@trendmicro.com says:

The vulnerability is a race condition between ets_qdisc_dequeue and
ets_qdisc_change. It leads to UAF on struct Qdisc object.
Attacker requires the capability to create new user and network namespace
in order to trigger the bug.
See my additional commentary at the end of the analysis.

Analysis:

static int ets_qdisc_change(struct Qdisc *sch, struct nlattr *opt,
struct netlink_ext_ack *extack)
{
...

  // (1) this lock is preventing .change handler (`ets_qdisc_change`)
  //to race with .dequeue handler (`ets_qdisc_dequeue`)
  sch_tree_lock(sch);

  for (i = nbands; i < oldbands; i++) {
          if (i >= q->nstrict && q->classes[i].qdisc->q.qlen)
                  list_del_init(&q->classes[i].alist);
          qdisc_purge_queue(q->classes[i].qdisc);
  }

  WRITE_ONCE(q->nbands, nbands);
  for (i = nstrict; i < q->nstrict; i++) {
          if (q->classes[i].qdisc->q.qlen) {
	      // (2) the class is added to the q->active
                  list_add_tail(&q->classes[i].alist, &q->active);
                  q->classes[i].deficit = quanta[i];
          }
  }
  WRITE_ONCE(q->nstrict, nstrict);
  memcpy(q->prio2band, priomap, sizeof(priomap));

  for (i = 0; i < q->nbands; i++)…

Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory 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-2025-71066 has been found in Kernel.
Attackers can target a specific entry point like ets_qdisc_dequeue over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 7.8/10.
What to do: upgrade Kernel to 5.10.248, 5.15.198, 6.1.160, 6.6.120, 6.12.64, 6.18.3 or later.
If unsure, ask your IT team or search "Kernel CVE-2025-71066" on the vendor's site.

CVE-2025-71066 (Kernel) — CWE-362 / CVSS v3 7.8
Attack vector: local / no user interaction
Attack surface: ets_qdisc_dequeue / ets_qdisc_change
Patched: 5.10.248, 5.15.198, 6.1.160, 6.6.120, 6.12.64, 6.18.3 — 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 (CWE-362) exists in Kernel. Attackers reach the vulnerable code path via ets_qdisc_dequeue.

📍 Affected scope

Check the vendor advisory for the affected versions of Kernel. Attack surface: ets_qdisc_dequeue / ets_qdisc_change.

🔥 Severity

Severity: High (CVSS 7.8/10). Successful exploitation can lead to full system takeover.

🔧 How to fix

Update to 5.10.248, 5.15.198, 6.1.160, 6.6.120, 6.12.64, 6.18.3.

🛡️ 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. 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. 2
    Apply patch patch 
    Upgrade Kernel to 5.10.248, 5.15.198, 6.1.160, 6.6.120, 6.12.64, 6.18.3

    ステージング環境で 5.10.248, 5.15.198, 6.1.160, 6.6.120, 6.12.64, 6.18.3 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. 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":"0"},{"fixed":"5.10.248"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.198"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.160"},{"fixed":"6.6.120"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.12.64"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.18.3"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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