# CVE-2026-64530: net/sched: cls_api: Handle TC_ACT_CONSUMED in tcf_qevent_handle > A use-after-free vulnerability in the Linux kernel's traffic control subsystem allows attackers to cause denial of service or execute code via crafted fragmented network traffic. - **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 26 Jul 2026 - **Updated:** 19 Oct 2026 - **Also known as:** AZL-93957, BELL-CVE-2026-64530, DEBIAN-CVE-2026-64530, GHSA-w5h3-gv63-49vp, RHSA-2026:47620, RHSA-2026:48222, RHSA-2026:49032, ROOT-OS-DEBIAN-12-CVE-2026-64530, ROOT-OS-DEBIAN-13-CVE-2026-64530, ROOT-OS-UBUNTU-2204-CVE-2026-64530, UBUNTU-CVE-2026-64530 ## What is CVE-2026-64530? CVE-2026-64530 is a critical use after free vulnerability in Linux, published on 26 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description In the Linux kernel, the following vulnerability has been resolved: net/sched: cls_api: Handle TC_ACT_CONSUMED in tcf_qevent_handle tcf_classify() can return TC_ACT_CONSUMED while the skb is held by the defragmentation engine (e.g. act_ct on out-of-order fragments). When that happens the skb is no longer owned by the caller and must not be touched again. tcf_qevent_handle() did not handle TC_ACT_CONSUMED: it fell through the switch and returned the skb to the caller as if classification had passed. The only qdisc that wires up qevents today is RED, via three call sites (qe_mark on RED_PROB_MARK/HARD_MARK, qe_early_drop on congestion_drop) red_enqueue() was continuing to operate on an skb it no longer owns in this case -- enqueueing it, dropping it, or updating statistics. Resulting in a UAF. tc qdisc add dev eth0 root handle 1: red ... qevent early_drop block 10 tc filter add block 10 ... action ct (with ct defrag enabled and traffic that produces out-of-order fragments, e.g. a fragmented UDP stream) Handle TC_ACT_CONSUMED in tcf_qevent_handle() the same way the ingress and egress fast paths do: treat it as stolen and return NULL without touching the skb. Unlike the TC_ACT_STOLEN case, the skb must not be dropped/freed here, as it is no longer owned by us. Weakness: CWE-416 (Use After Free) ## Which versions are affected by CVE-2026-64530? | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `kernel` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-64k` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-64k-core` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-64k-debug` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-64k-debug-core` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-64k-debug-debuginfo` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-64k-debug-devel` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-64k-debug-devel-matched` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-64k-debug-modules` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-64k-debug-modules-core` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-64k-debug-modules-extra` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-64k-debuginfo` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-64k-devel` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-64k-devel-matched` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-64k-modules` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-64k-modules-core` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-64k-modules-extra` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-abi-stablelists` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-core` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-debug` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-debug-core` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-debug-debuginfo` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-debug-devel` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-debug-devel-matched` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-debug-modules` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-debug-modules-core` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-debug-modules-extra` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-debug-uki-virt` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-debuginfo` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-debuginfo-common-aarch64` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-debuginfo-common-ppc64le` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-debuginfo-common-s390x` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-debuginfo-common-x86_64` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-devel` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-devel-matched` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-doc` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-modules` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-modules-core` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-modules-extra` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | | `kernel-rt` | Red Hat:enterprise_linux_eus:10.0 | All versions | 0:6.12.0-55.93.1.el10_0 | ## How do I fix CVE-2026-64530? Apply the vendor's patch. ## Is CVE-2026-64530 being exploited? There is no known exploitation of CVE-2026-64530 in the wild and no public exploit code. ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-64530 and fix it if it is affected. What it is: CVE-2026-64530 is a critical use after free vulnerability in Linux, published on 26 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2026-64530 in the wild and no public exploit code. Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-64530/ (Markdown: https://insights.sbomify.com/CVE-2026-64530/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64530 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64530 - OSV: https://osv.dev/vulnerability/CVE-2026-64530 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-64530/ Summaries are generated and may contain mistakes; the official description above is the record.