# CVE-2026-53011: net/sched: taprio: fix use-after-free in advance_sched() on schedule switch

> A use-after-free in the Linux kernel's taprio scheduler allows attackers to potentially execute code or escalate privileges during schedule switches.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Jun 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-53011, DEBIAN-CVE-2026-53011, GHSA-g35r-7cv7-8x5x, ROOT-OS-DEBIAN-11-CVE-2026-53011, ROOT-OS-DEBIAN-12-CVE-2026-53011, ROOT-OS-UBUNTU-2204-CVE-2026-53011, ROOT-OS-UBUNTU-2404-CVE-2026-53011, UBUNTU-CVE-2026-53011

## What is CVE-2026-53011?

CVE-2026-53011 is a high-severity use after free vulnerability in Linux kernel, published on 24 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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

net/sched: taprio: fix use-after-free in advance_sched() on schedule switch

In advance_sched(), when should_change_schedules() returns true,
switch_schedules() is called to promote the admin schedule to oper.
switch_schedules() queues the old oper schedule for RCU freeing via
call_rcu(), but 'next' still points into an entry of the old oper
schedule. The subsequent 'next->end_time = end_time' and
rcu_assign_pointer(q->current_entry, next) are use-after-free.

Fix this by selecting 'next' from the new oper schedule immediately
after switch_schedules(), and using its pre-calculated end_time.
setup_first_end_time() sets the first entry's end_time to
base_time + interval when the schedule is installed, so the value
is already correct.

The deleted 'end_time = sched_base_time(admin)' assignment was also
harmful independently: it would overwrite the new first entry's
pre-calculated end_time with just base_time.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-53011?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-53011?

Apply the vendor's patch.

## Is CVE-2026-53011 being exploited?

There is no known exploitation of CVE-2026-53011 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53011 and fix it if it is affected.

What it is: CVE-2026-53011 is a high-severity use after free vulnerability in Linux kernel, published on 24 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-53011 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-53011/ (Markdown: https://insights.sbomify.com/CVE-2026-53011/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53011
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53011
- OSV: https://osv.dev/vulnerability/CVE-2026-53011

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53011/
Summaries are generated and may contain mistakes; the official description above is the record.