# CVE-2026-53085: bpf: fix mm lifecycle in open-coded task_vma iterator

> A use-after-free in the Linux kernel BPF task_vma iterator allows attackers to execute arbitrary code or escalate privileges via concurrent task exit.

- **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-2026-53085, DEBIAN-CVE-2026-53085, GHSA-44fh-c439-xq8f, ROOT-OS-UBUNTU-2404-CVE-2026-53085, UBUNTU-CVE-2026-53085

## What is CVE-2026-53085?

CVE-2026-53085 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:

bpf: fix mm lifecycle in open-coded task_vma iterator

The open-coded task_vma iterator reads task->mm locklessly and acquires
mmap_read_trylock() but never calls mmget(). If the task exits
concurrently, the mm_struct can be freed as it is not
SLAB_TYPESAFE_BY_RCU, resulting in a use-after-free.

Safely read task->mm with a trylock on alloc_lock and acquire an mm
reference. Drop the reference via bpf_iter_mmput_async() in _destroy()
and error paths. bpf_iter_mmput_async() is a local wrapper around
mmput_async() with a fallback to mmput() on !CONFIG_MMU.

Reject irqs-disabled contexts (including NMI) up front. Operations used
by _next() and _destroy() (mmap_read_unlock, bpf_iter_mmput_async)
take spinlocks with IRQs disabled (pool->lock, pi_lock). Running from
NMI or from a tracepoint that fires with those locks held could
deadlock.

A trylock on alloc_lock is used instead of the blocking task_lock()
(get_task_mm) to avoid a deadlock when a softirq BPF program iterates
a task that already holds its alloc_lock on the same CPU.

Weakness: CWE-416 (Use After Free), CWE-825 (Expired Pointer Dereference)

## Which versions are affected by CVE-2026-53085?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-53085?

Apply the vendor's patch.

## Is CVE-2026-53085 being exploited?

There is no known exploitation of CVE-2026-53085 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-2026-53085 and fix it if it is affected.

What it is: CVE-2026-53085 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-2026-53085 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-2026-53085/ (Markdown: https://insights.sbomify.com/CVE-2026-53085/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53085
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53085
- OSV: https://osv.dev/vulnerability/CVE-2026-53085

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53085/
Summaries are generated and may contain mistakes; the official description above is the record.